170 BRITISH CICAD.E. 



confined to the middle division. The so-called Pecten- 

 beds, above noted, are laminated in texture, and con- 

 tain, beside insects, carbonized stems and seed-vessels 

 of various plants. The Pm'beck-beds at Eidgway, near 

 Weymouth, are also rich in remains of insects. As 

 many as seventy different elytra have been counted, all 

 crowded on the surface of one small slab.* 



The tables contained in Prof. Westwood's memoir 

 may be consulted with advantage as to the exact 

 localities from which the fossil insects of his memoir 

 have been taken. Some general reasons are given by 

 him for the conclusion, that the numerous insects of 

 the Lower and the Middle Purbecks (including those 

 of the Ridgway quarries) all belong to one fauna. 



In another place I have shown that Aphides, also, 

 are duly represented in these same beds. Similar 

 climatal conditions obviously permitted the existence of 

 these two insect families side by side. The examination 

 of some hundreds of these fossil remains suggested a 

 temperate climate, a belief which is the more likely 

 to be true from the absence of tropical singing Cicadae 

 and large locusts. 



The cause of the occurrence of such isolated masses 

 of beetles, flies, and Libellulge still rests in the same 

 obscurity as that which led to the preservation of 

 similar remains in. the limestone of Solenhofen, and 

 the lithographic stones of Central Europe. Although 

 chitin is, in a sense, indestructible, it is remarkable 

 that neither legs, bodies, nor antenna are here pre- 

 served. At least, amongst the Coleoptera, such parts 

 might have been expected to be preserved and united 

 to the bodies. 



■■'■ The reader is referred for more information to the Eev. J. H. 

 Austen's hst, Nos. 104, 106, 113, 116, 119, in the ' Guide to the Isle of 

 Purbeck,' 1852. 



