GEOLOGY OF GLOIJCEStERSHIRE. 



231 



Gretton, masses of a small species of Cidaris, with attached spines, occur. 

 Traversing this shale is a comparatiyely thin bacd of nodular lime- 

 stone, white on the upper and under surfaces, and blue in the centre, 

 very hard when first dug out, but, when weathered, splitting into thin 

 slaty masses, which are sometimes crowded with minute univalve 

 shells. But the most interesting organic remains which have 

 been found in it are those of fish and insects, both of which are 

 sometimes met with nearly entire. Amongst the former the little 

 Leptolepis concentricus is the most common, although other genera 

 and species have been found. Amongst the latter the fine and unique 

 dragon-fly, ^slina Brodiei,'^'- is the most worthy of notice. Detached 

 wings of Libellulidce, and wings and bodies of insects of other families 

 and orders, are associated with the more common kinds, but rarely 

 found entire, notwithstanding the nervures of the wings are often 

 retained with wonderful delicacy on the stone; and it may well 

 excite our surprise that such fragile creatures as insects should be 

 preserved at all. The land from whence they were carried out to sea, 

 or over which they winged their flight, was probably not far distant ; 

 and the adjacent Malvems, and the Silurian country on the west, 

 apparently formed the coast on which the Lias was deposited. A few 

 imperfect fragments of plants are the only other terrestrial relics 

 as yet detected ; but so little of the upper Lias is exposed in 

 Gloucestershire, that no fair estimate can be given of the cotemporary 

 forms of animal life which may have inhabited the land at that epoch. 



-Much more might be said about these insects, but as we hope, in a 

 future communication, to describe them more fully, we shall defer the 

 details until then. 



The internal shells of a species of cuttle-fish, one of the curious tribe 

 of Cephalapods to which the fossil Ammonites and Belemnites belong, 

 are now and then found in tolerable perfection in this limestone. Con- 

 nected with this horny pen is a singular apparatus termed the ink-bag, 

 which, in the recent animal, is used as a means of defence against the 

 attacks of its enemies. This organ sometimes occurs in such perfection 

 in the extinct species that its contents may still be used as a pigment ; 

 and we have seen a sketch of one of these fossil pens with 

 its associated ink-bag, drawn by our friend Professor Buckman with 



This is described and figured in the Quart. Journ. Geo, Soc. 1848, Vol. V., 

 pi. 2, p. 35. R.P.B. 



