TRANSACTIONS FLORA OF THE CORALLINE A N D RED CRAGS OF EAST SUFFOLK F. W.
SIMPSON
THE Coralline Crag of East Suffolk is the earliest of the Suffolk Crags, and is a rieh fossiliferous deposit of the Late Pliocene. It is often cemented together by corals and the remains of other animals to form a hard rock which was once quarried for building stone. This use can be seen in several churches : Chillesford, Orford, and Ramsholt are examples. The Coralline Crag can be examined in old excavations at Sudbourne, Orford, Gedgrave, and Shottisham, and in cliff exposures at Aldeburgh and formerly at Ramsholt. It is usually covered by later deposits and rarely lies at or very near the surface over large areas, except at Sudbourne Park. The Red Crag is a much later deposit of the Lower Pleistocene and extends over a greater area of the coastal districts of East Suffolk, roughly south of Aldeburgh and into North Essex. It is usually observed as a sandy and shelly rieh reddish-brown deposit, and can be traced inland along the river and stream Valleys—in the Aide and its tributaries at Saxmundham and Parham ; the Deben at Charsfield and Clopton ; the Finn at Witnesham ; the Gipping at Battisford ; the Stour at Nayland and Bures ; the Brett at Layham ; and the Box at Boxford and Leavenheath. The shelly crag is covered over much of this area by glacial drift. However, it is found that some crag sands are no longer " shelly " and have been " deealeified " by the action of rain-water, and can easily be mistaken for glacial drift. North of Aldeburgh is the Norwich Crag, which used to be exposed in the cliff at Thorpeness. This crag extends into the Waveney Valley and across the valley into Norfolk. It comes to the surface at Sizewell and Leiston Common. There are important excavations at Holton, near Haiesworth, and exposures in the cliffs at Easton Bavents, near Southwold. Deealeified Norwich Crag sands occur in the Blyth Valley at Blyford, Wenhaston, Blythburgh, Reydon, and elsewhere in the area. The Chillesford Beds are the latest deposits in the Crag sequence. These deposits consist of shelly sands, pure sands, pebble beds, and clays, and occur near the surface only in small areas at Chillesford and near Aldeburgh. Deposits related to this epoch occur north of Southwold.
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Transactions of the Suffolk Naturalists',
Vol. 73, Part 1
The Crags are rieh in minerals, especially calcium, iron, and phosphorus and situated as they are in the dry, sunny coastal area of the county—favour the growth of certain species of plants. The general flora bears much similarity to that found in Breckland. The landscape has changed greatly during the forty years I have known the area. Extensive heathland and other waste areas have either been ploughed up or planted with coniferous trees so that only scraps of the relic flora exist today. The majority of the old pits which were worked for coprolites in the 19th Century have been destroyed or filled up with rubbish, or are overgrown with nettles, brambles, and eiders, or used for the storage of farming equipment and housing pigs and poultry. About thirty years ago I discovered a habitat on the Red Crag near Woodbridge where there was an interesting and unusual flora which one does not associate with the district. The discovery of this " relic flora " spurred me to search as many sites as possible on the Coralline and Red Crag, and over the years I have visited practically every pit or exposure on one or more occasion, hoping to find further traces of this type of flora. Before the Second World War the old flora of the Coralline Crag was well developed at Sudbourne, especially in the Park which has now been ploughed-up. There were also areas of heathland and quarries around Sudbourne and Gedgrave which are now covered by plantations. Some of the old flora has just managed to survive in a few restricted areas. Species which can still be found include :— Sickle Medick (Medicago falcatä) and the hybrid (M.falcata x sativa), Dwarf Thistle (Cirsium acaulon), Carline Thistle (Carlina vulgaris), Zigzag Clover (Trifolium medium), Wild Basil (Clinopodium vulgare), Wild Thyme (Thymus serpyllum), and Greater Knapweed (Centaurea scabiosa). Basilthyme (Acinos arvensis) and Lizard Orchid (Himantoglossum hircinum) are now extinet. The flora of the Red Crag is characterised by a number of plants which although they occur elsewhere in the county, are often more abundant in the Crag country near the coast. The following are some of the special plants of the open country, waste places and disturbed ground around the old pits :— Hound'stongue (Cynoglossum ofßcinale), Bugloss (Lycopsis arvensis), Viper's Bugloss (Echium vulgare), Common Storksbill (Erodium cicutarium), Thyme-leaved Sandwort (Arenaria serpyllifolia), Dyer's Rocket (Reseda luteola), Wild Mignonette (R. lutea), Spotted Medick (Medicago arabica) Spring Vetch (Vicia lathyroides), Birdsfoot (Ornithopus perpusillus), Scotch Thistle (Onopordum acanthium), Musk Thistle (Carduus nutans), Slender Thistle (C. tenuiflorus), Milk Thistle (Silybum marianum) at Bawdsey and Blyford, Henbane (Hyoscyanus niger) at Chillesford
FLORA OF CORALLINE AND RED CRAGS
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and Ramsholt. White Bryony (Bryonia dioica) is common in overgrown pits. Frequent weeds of the arable land between Felixstowe and Orford including Night Flowering Campion (Melanirium noctißorum) and Stinkweed (Diplotaxis muralis). Some plants which are uncommon off their usual Suffolk soils can be found occasionally in the Crag areas : the Cowslip (Primula veris) at Butley, Sudbourne, and Tattingstone, Bladder Campion (Silene cucubalus) at Felixstowe, Bawdsey, and Hollesley, Salad Burnet (Poterium sanguisorba) at Bawdsey, Greater Knapweed (Centaurea scabiosa) at Alderton, with the rare hybrid Centaurea scabiosa X nigra. The parasitic Tall Broomrape (Orobanche elatior) frequently appears. The Lizard Orchid (Himantoglossum hircinum) recorded many years ago by Miss E. Rowling at Tattingstone and refound by A. L. Bull, was associated with the Red Crag. The habitat has now been destroyed. I once found a single specimen of the Pyramidal Orchid (Anacamptis pyramidalis) in the large crag pit at Newbourne which is now occupied by buildings of the Waterworks. Over some areas of the crag sands at Butley, Chilesford, Sudbourne, Iken, Snape, and elsewhere, the Sand Sedge (Carex arenaria) is dominant. Field Mouse-ear Chickweed (Cerastium arvense) used to occur at Butley and Chilesford, but I have not Seen aflowerfor many years. Before the last War there were very rieh "floral" meadows and pastures in the Crag Country, especialy at Butley and Chilesford, where one could observe thousands of magnificent spikes of Marsh Orchis (Dactylorchis praetermissä) and many hybrids (D. maculata X praetermissä). Bee Orchids (Ophrys apifera) were occasionally found. This attractive area has changed greatly in recent years and is now mainly arable, hedges and trees having been removed and the marshes drained. About forty years ago at Waldringfield and Martlesham were a few rieh meadows " on the Crag ". In two particular meadows I found large numbers of Early Purple Orchis (Orchis mascula) and Green Winged Orchis (Orchis morio) and once the rare hybrid O. mascula X morio. Mention must be made of the woods on the Crag. A dry wood usually has little of interest, but a moist wood with Crag springs can be very rewarding. The Crag springs are a feature of the Valleys where the Red Crag deposits rest on the London Clay. The spring water is rieh in mineral salts, and the flow remains fairly constant even in the driest summers. The springs do not freeze in the coldest winters, the temperature of the water remains fairly constant—between 40°F. to 45°F. throughout the year. I have often found the water from these springs cold and refreshing on a hot summer day. Felixstowe Spa water, which used to be sold at the Spa Pavilion, was derived from a small
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Transactions
of the Suffolk
Naturalists',
Vol. 13, Part I
Crag spring rieh in iron and phosphates. T h e frequency of both the Opposite and Alternate-leaved Golden Saxifrages (Chrysosplenium oppositifolium, C. alternifolium) in Fast Suffolk is entirely due to the Crag springs and small associated streams. One or both of the species can be f o u n d in almost every parish where there are Red Crag Valleys and springs. Another plant which is also associated with the Crag springs and grows under very similar conditions, is the Large Bitter-cress (Cardamine amara) which occurs at Stoke-by-Nayland, Polstead, Freston, Chelmondiston, Bentley, Playford, and elsewhere. Woodland species I have found associated with these deposits include H e r b Paris {Paris quadrifolid) at Chillesford, Greater Butterfly Orchid {Piatanthera chlorantha), Fly Orchid {Ophrys insectifera), Twayblade {Listera ovata), Solomon's Seal {Polygonatum multiflorum) and Adder's T o n g u e {Ophioglossum vulgatum).