240 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Jail. 9, 



The following divisions (see Section, p. 242) of the oolitic strata 

 at Leckhampton Hill, near Cheltenham, where the shelly freestone 

 may be most advantageously studied, have been principally proposed 

 and adopted by the authors of the work above referred to ; although 

 later investigations by Mr. Strickland prove, that their relative thick- 

 ness is greater than has been generally supposed, and I have there- 

 fore followed his admeasurements. The summit of the hill is capped 

 by a rough, gritty stone, loaded with casts of Trigonia cost at a and 

 T. clavellata ; but neither this, nor the thin and very fossiliferous 

 band of clay which separates it from the "Gryphite grit," are well 

 developed in this section. Hence the latter (No. 2 of Section, p. 242) 

 may here be more correctly said to be the first stratum in descend- 

 ing order. It is a coarse calcareous grit, full of the Gryphcea cym- 

 bium and numerous other shells, the former of which is character- 

 istic. The oolite marl*, or cream-coloured marly oolite, which suc- 

 ceeds (No. 5 of Section, p. 242), is in places hard and concretionary, 

 but often friable, and breaks up irregularly by the action of frost : it 

 may be estimated at seventeen feet in thickness. It contains a large 

 species of Natica, Plagiostoma, Area, Hostellaria, and Terebratula 

 fimbria ; the last, which occurs in profusion, marks and is confined to 

 this bed. It is locally rich in corals, one species occurring in large 

 blocks exceeding two feet in length, and generally speaking, like the 

 Pisolite, must have formed a coral-reef in the ancient ocean. It has 

 also been subject to much denudation, not only when it first emerged 

 from the waves, but probably at a later period ; for the corals and 

 shells are frequently water-worn, and many of the former enter largely 

 into the composition of the oolitic gravel which fills up hollows in 

 the lias plain beneath. Towards the south this marl is not so readily 

 traced, until it appears again at Crickley and Birdlip, the top of the 

 hill being composed of the great and more important underlying mass, 

 which forms the thickest division of the inferior oolite, upwards of a 

 hundred feet thick, and which is used for building and other purposes. 

 It is ordinarily termed "freestone" (No. 6 of Section), and in part 

 forms a fine-grained, light-coloured oolite, closely resembling the 

 Bath freestone, and is nowhere absolutely destitute of organic re- 

 mains, the harder stone being made up of comminuted fragments of 

 shells and corals. The more perfect specimens are almost entirely 

 confined to two or more shelly masses, one of which may be seen at 

 the summit of the hill on the south, where it crops out, and has been 

 broken up and water-worn. There it becomes flaggy, and bears a 

 striking mineralogical resemblance to certain beds in the Forest marble 

 and Great oolite, and this is the prevailing character of these subor- 

 dinate groups. One of these upper shelly layers may be traced from 



* The oolite marl reappears near Stroud, and, with very shght lithological va- 

 riations, is similar to that at Leckhampton. It affords, like the latter, many shells 

 pecuUar to it, but they are more numerous and better preserved. Mr. Lycett's fine 

 collection contains several species which have not yet been observed in the vicinity 

 of Cheltenham. Viewed as a whole, the shells are remarkably distinct from all 

 other beds in the great and inferior oolite. Mr. Lycett possesses more than 130 

 species from this stratum. 



