92 OUR COMMON BRITISH FOSSILS. 



geologist at Hackness, Ayton (where the best speci- 

 mens are obtainable), Seamer, Toton, Wykeham, and 

 Brompton localities which are close together. The 

 Thamnastr&a is broken up to mend the roads with ; 

 and the student will find capital geologizing in the 

 heaps of stone by the roadside, which await parochial 

 relief to break them up and prepare them. 



Higher up in Oolitic strata, localities where fossil 



Fig. 71. -Isastraa insignis (Lower Lias). 



corals can be collected are in the neighbourhood of 

 Cirencester and Bath ; at the latter place the rock is 

 frequently full of Calamopkyllia, resembling petrified 

 straws. The very name of one division of this in- 

 teresting formation " the Coral Rag " indicates how 

 plentiful these kinds of fossils are in it. About four- 

 teen different species, chiefly Astrceidtz, have been 



