446 J. Prestwich, Esq., on the 



beds of shale, and traces of coal ; but they are almost totally destitute of organic remains. In 

 the Lower New Red Sandstone, into which the coal-measures apparently pass, I have met with a 

 few imperfect impressions of soft monocotyledonous plants. 



I have not noticed the fresh-water limestone in the foregoing series, as in the northern dis- 

 tricts which afforded the principal materials for the previous observations, this calcareous band 

 has not been found. 



In it have been discovered the Microconchus carhonarius, a species of Cyclas, with the Cypris 

 inflata*. 



Having now enumerated the characteristic organic remains of each bed, it remains to notice only 

 those fossils, the proper place of which in the series is not correctly known. In the collection 

 of Mr. Anstice are two remarkably interesting and singular fossils, called by Dr. Buckland 

 Curculloides Ansticii and Curculloides Prestvicii. They are the oldest known insects. In the first 

 part of this paper, read before the Society in 1834, I mentioned these fossils, but was unable to 

 state to what genus they belonged. Mr. Mantell says that he has discovered in an ironstone 

 nodule from Coalbrook Dale, the wing of a Neuropterous insect, closely resembling that of the 

 living Corydalis of Carolinaf. 



The specimen of Triconocarpum ovatum figured in the Fossil Flora of Great Britain (Plate 

 CXLII. fig. A.), is also from the Coalbrook coal-field, and is in the collection of Mr. Anstice. It 

 is supposed by Messrs. Lindley and Hutton to have been the fruit of a palm, as recent palms have 

 a three-ribbed thick shell, containing a single seed. 



From the length of time since the above fossils were found, the stratum in which they were 

 procured, cannot be ascertained. It was most probably the Hailstone, or the White Flats. 



With reg-ard to the habitats, and state of preservation of the fossils, it may 

 be repeated, that the ironstone nodules form the principal depositories both 

 for the animal and vegetable remains, which generally present very sharp and 

 distinct impressions and casts, almost always perfectly free from their original 

 substance. In the shales in which the ironstones are imbedded, I have scarcely 

 found a single vegetable impression. A few fish-scales, shells, and teeth, are 

 sometimes, though rarely, met with in the Penneystone, Top coal, and Black- 

 stone shales ; and some of the thin bands of crushed Unios exist in dark bitu- 

 minous shales. The casts of Lycopodiaceae and testacea are often filled with 

 crystallized sulphuret of zinc, and sometimes with carbonate of iron, and car- 

 bonate of lime. But one of the most common accompaniments of the casts of 

 animal exuviae, is a white, impalpable powder, in which I have detected silica, 

 alumina, and potash; thus agreeing with the mineral found by M. Guellemin 

 in the mines of Antin, and termed by him Pholenite. The shells of the Pen- 

 neystone measure are almost always ironstone casts ; those belonging to the 

 bivalves being generally external, but sometimes internal; and the muscular 

 attachment is frequently marked by a black spot. Some of the larger shells 

 are found in the shale, but the majority are imbedded in the ironstone nodules. 

 In most of the shales and indurated clays in immediate contact with the coal, 

 * Mr. Murchison's Silurian System, p. 84. f Wonders of Geology, p. 593. 



