458 E. Wilson — Colour-hands in Waldheimia. 



similar to that above described, and a good supply of water was 

 obtained which rises above the surface of the ground. 



It is also worthy of note that this emergent tract of Vectian sand 

 is the most westerly exposure yet known, with the exception of 

 that near Lulworth Cove, which, however, is of much smaller size, 

 compared with the tract above mentioned. It happens too that this 

 tract, and that near Lulworth, are almost exactly on the same line 

 of longitude. 



Considering its position, the amount of glauconite present, the 

 fineness of the sand, and the existence of interstratified clay are 

 remarkable facts, suggesting that the deposit was formed at some 

 distance from a shore-line. Comparison with the exposures near 

 Devizes and Seend certainly suggests that the latter were formed in 

 much shallower water and much nearer a coast-line. 



YI. — On a Specimen of Walbheimia perforata (Piettk), showing 

 Original Colour-makkings. 



By Edward Wilson, F.G.S., 

 Curator of the Bristol Museum. 



THE retention of the original colour-markings amongst fossil 

 Brachiopoda is a somewhat rare occurrence : the following 

 striking instance therefore seems worthy of record. 



It is true that Deslongchamps in the Paleontologie Frangaise 

 mentions the colours of a number of Jurassic Brachiopods, but in 

 nearly all these cases the colours are spoken of as if uniformly dis- 

 tributed and not patterned over the shells,^ and therefore we cannot 

 be sure that they are original and not subsequently produced. 



Of British fossil Brachiopods which show the colour-markings, 

 Terehratula Jiastata and Discina nitida respectively from the Carboni- 

 ferous Limestone of Longnor, Derbyshire and Hamilton, Scotland, 

 Terehratula intermedia from the Corubrash of Wollaston, and Tere- 

 hratula biplicata from the Upper Greensand of Cambridgeshire, are 

 examples.* In these cases the colour-marks are generally in the 

 form of radial, i.e. vertical bands or striee. 



The specimen to which I now call attention is one belonging to 

 the species Waldheimia perforata, Piette, and comes from the Lower 

 Lias of Bitton, Gloucestershire. 



The colour indications on this shell are in the form of clearly 

 defined concentric bands of black and white of varying breadth, 

 conforming approximately but not rigidly with the lines of growth. 

 The bands of colour are bilaterally symmetrical, and, what is still 

 more important as indicating that they are original, correspond in 

 the two valves, except that as we should expect they are broader in 

 the larger and more rapidly growing ventral valve, and show a 

 tendency in that valve to split up into smaller rings. Commencing 

 at the beaks we have in each valve a white circular area crossed by 



^ The colour of Waldheimia perforata for example is given by this author as 

 " brun fonce violace." 



2 Vide T. Davidson, Palsenot. Soc, British Fossil Brachiopoda, vols. i. ii. and iv. 



