TAYLOR — GEOLOGT OF CASTLETON, DERBYSHIRE. 87 



in the richer pastures. The number of mosses is exceedingly great. 

 The beautiful Bryum dendroides and others abound in the moister 

 spots of the Cave Dale. In fact, the botanical character of the vege- 

 tation hereabout is so peculiar to the three formations which are 

 found as to form a geological map to the underhiug rocks, coloured 

 bj nature herself! The limestone clothed with its short and beautiful 

 carpet of green ; the black shales of the Yoredale rocks covered by 

 their stunted and brown vegetation ; and the millstone-grit in the 

 glowing summer-time quite purple with the flowers of the heather. 

 And for land shells no other locality can compete with it. From the 

 robust Helix aspersa to the diminutive Fupa numerous species in- 

 tervene ; some of them, such as Claiisilia and Pupa, being more nu- 

 merous in individuals than any other place that I have visited. 



But to the geologist the rocks present treasures of fossils most 

 beautifully preserved. I have found the Terebratula liastata retaining 

 its purple colour-bands as beautifully as when alive in the carboni- 

 ferous seas ; and in some places every slab that is turned up is 

 matted with Eetepora and Fenestrella. Coming here from Manchester, 

 along the new road from Chapel-en-le-Frith, the first place where we 

 meet with the limestone is about a mile and a half distant from the 

 town. This hill, Treclitf, is about six hundred feet in height, and the 

 dip of the beds is about '2b° in a direction JSF.N.E. It is in this hill 

 that the " Blue John " mines are situated ; and is the only locality 

 in the country where this peculiar mineral is met with. It lies in 

 "pipe-veins," having the same inclination as the rocks which the 

 veins traverse. One of these veins lies in a sort of clayey stratum, 

 and another seems to be imbedded in the nodule state in a mass 

 of indurated debris. Besides these, the whole of the limestone 

 masses are fractured and cracked, and, in addition to the pipes, the 

 sides of the cavities are lined with the m.ost perfect and beautiful sky- 

 blue cubes of fluor, and the rhombic crystals of calcite. I remember 

 scarcely anything with greater pleasure then an adventure in search 

 of minerals a year or two ago, in one of these caverns, which was 

 richly rewarded. Witherite, fluor-spar, varying in colour from trans^ 

 parency to rose, blue, violet and other colours, selenite, and occa- 

 sionally phosphate of lead, are all found in the lead-mines of the neigh- 

 bourhood. Some varieties of calcspar have the property of double 

 refraction, like Iceland spar. 



Nearly all the characteristic fossils of the carboniferous limestone 

 abound, as m.ay be seen by glancing at the names of the localities 

 given in Professor Phillips's ' Geology of Yorkshire.' The richest 

 localities for obtaining them is just below the "Blue John cavern," and 

 in the gorge at the back of the town, which goes by the name of 

 the Cave Pale. In geologizing along the side of TreclifF hill, one 

 cannot but be struck with the various groups of fossils which the 

 diff'erent beds present. The loiver beds contain great quantities of 

 PJiillipsia— heads, carapaces, etc., being very frequently met with, and 

 occasionally they are found whole. Just as we should have expected 

 from knowing that the family of Trilobites died out with the moun- 



