32 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 31, 



nearly perfect Libellula and a new species of Leptolepis in that de- 

 posit, for an account of which I am indebted to the kindness of Mr. 

 Westwood and Sir Philip Egerton. 



The upper lias in Gloucestershire is of considerable extent and 

 thickness, and may be traced along the lower escarpments of the 

 Cotswolds between the inferior oolite and the marlstone; owing how- 

 ever to the few sections exposed, the various fossils which it affords 

 have been chiefly obtained from one particular locality. It also 

 caps detached outliers a few miles from this range, and if a line 

 be drawn from the summit of any one of them to a parallel point in 

 the opposite hills, the strata will be found to correspond ; and hence 

 we may infer that they were formerly attached to the main chain, the 

 intervening space having been subsequently denuded, though there 

 are few traces of liassic boulders in the adjacent valley. In the two 

 outliers at Churchdown and Hobinswood Hill near Gloucester, the 

 upper lias is comparatively thin, the shale resting conformably on the 

 marlstone, scarcely averaging eight feet, and the loose pieces of the 

 ''Jish-bed,''' not exceeding a few inches, but containing the usual and 

 characteristic fossils*. I have not been able to detect any traces of 

 this stratum further south ; at least, its outcrop is not anywhere seen ; 

 although the marlstone is largely developed in the neighbourhood of 

 Wotton-under-edge, and the lower lias, especially the " insect lime- 

 stone," extends over a considerable portion of the vale, and contains 

 some beautiful portions of insects, particularly wings allied apparently 

 to Phryganea. 



At Dumbleton, twelve miles north-east of Cheltenham, where an- 

 other and larger outlier is exposed, the upper lias shales are about 

 150 feet thick, and include an irregular band of limestone, locally 

 termed "the fish-bed," above alluded to, which varies from four to 

 fifteen inches in thickness. It occurs near the lower part of the shale, 

 running at irregular intervals, and here and there forming romided 

 blocks of some size. The outer surface is soft and of a yellow colour, 

 but towards the interior it becomes hard and assumes a blue tinge. 

 It has an irregular fracture when dry, and as it is readily acted upon 

 by frost, it does not make a good building-stone, though it would 

 burn into lime if required. The clay contains a great many casts of 

 Ammonites and other shells, but the best-preserved and remarkable 

 fossils are confined to this limestone. Of these the insects are per- 

 haps most worthy of notice, though hitherto confined chiefly to 

 single wings and elytra, to which the fine specimen about to be de- 

 scribed forms at present a unique exception, and is, as far as I am 

 aware, the first nearly perfect Neuropterous insect found in this 

 country. 



Mr. Westwood observes, that " it possesses an arrangement of the 

 wing-veins differing from that of any English species, and also from 

 any foreign species known to me ; but it comes nearest to the small 

 British Libellulce forming the genus Biplax. The wings are broad 

 and nearly equal. The third and fourth veins of the upper wings 

 are curved towards the inner margin near the base. The stigmata are 



* See Mr. Buckman's paper, Proc. Geol. Soc. vol. iv. part i. p. 211. 



