Yol. 54.] IN THE CARBONIFEEOUS LIMESTONE or DERBYSHIRE. 177 



No. 587, 2 inches below No. 586, is a piece of limestone enclosed 

 in the quartz-rock, and gradually shading off into it. Several 

 encrinite-stems are seen in a hand-specimen. Under the microscope 

 the base is mainly crystalline calcite, with no traces of organisms — 

 except an encrinite-stem which contains a crystal of quartz. ^ The 

 quartz-crystals have regular boundaries, and occur singly or in 

 groups or clusters. 



No. 588, sp. gr. 2-63, 2 yards below No. 587, is a quartzose 

 limestone. It contains traces of organisms, probably sections of 

 shells which are partly replaced by masses of quartz-crystals and 

 single crystals, and also a section of an encrinite-stem. 



No. 589, sp. gr. 2*63, 2 yards below No. 587. A foraminiferal 

 limestone. The quartz occurs mostly in separate crystals, which 

 have well-defined crystalline boundaries. A characteristic of this 

 slice is the great number of foraminifera which contain and are 

 penetrated by quartz-crystals, clearly indicating that the quartz is 

 secondary and later than the organisms, and is in fact a replace- 

 ment of them. There is very little of the aggregate of quartz- 

 grains as seen in the two previous slices. The residue, after 

 solution in hydrochloric acid, consists entirely of quartz-crystals ; 

 these vary in size from '60 X "09 mm. to '07 x '02 mm. 



No. 590, on the same horizon as the preceding and a yard or so 

 distant, sp. gr. 2*587. Limestone containing foraminifera, oolitic 

 grains, and shell-fragments. Some of the organisms are penetrated 

 by quartz-crystals. The quartz occurs also in groups or bunches of 

 crystals, which, under polarized light, form a mosaic, and in the 

 residue occur as a bundle of quartz-crystals, the pyramidal points 

 projecting outward in every possible direction. The residue is 

 quartz only, in bunches and separate crystals, the latter varying 

 in size from -32 x "06 mm. to -03 x *01 mm. A few chert- 

 nodules were seen in some of the quartz-rock on this side of the 

 valley. The rock weathers black, and often contains blue fluor. 

 It shows no traces of bedding. The softer parts weather out, 

 leaving a vesicular or pitted surface, similar to that of the Pounder 

 Lane rock. Some lower beds, a short distance down the Dale, consist 

 of limestone with partings and nodules of chert containing casts of 

 encrinite-stems. 



(h) Bathamgate (6-iiicli Map 15, N.E.) : about 800 feet 

 south of Moss Kake. 



The quartz-rock occurs in isolated blocks at the western end of 

 the Rake. 



Nos. 577, 580, sp. gr. 2*50. These are similar in structure to 

 the Top Lift quartz-rock. 



No. 578, sp. gr. 2-47. This and No. 579 differ from the 

 specimens previously described. The rock consists mainly of large 

 quartz-grains forming a granitic structure, with smaller ones of 

 sometimes hexagonal outline embedded in, and filling spaces 



