1814.] Outlines of the Mineralogy of the Ochil Hills. 121 



The mimerous cavities contained in it are lined with white ame- 

 thyst, flesh-red calcareous spar, white felspar, chalcedony, red 

 flint, and common quartz. The chalcedony appears to have been 

 first deposited, and the quartz to have bctn tiic last. 



The amygdaloid sometimes becomes porphyritic, contaiuing 

 crystals of felspar. 



It is difficult to assign to this rock its correct geognostic position. 

 At Parton Craigs it is below claystone porphyry. Near Newport it 

 alternates with basaltic clinkstone. At the western extremity of 

 Wormit Bay it is below the claystone, through which it seems to be 

 connected with the tuff on the one hand, and with the claystone 

 porphyry on the other. On the water of Fargs, which runs from 

 Damhead* to Abernethy, it occurs resting on a variety of green- 

 stone, which is connected with the clinkstone. In this last situation 

 it possesses a great variety of characters, being extremely coarse at 

 one point, where a bed of clay porphyry rests upon it. More to 

 the southward tlie vesicles in the amygdaloid become very distinct, 

 and contain a flcbh-red variety of felspar. 



This rock is traversed by veins of calcareous spar, which exhibit 

 a sea-green colour when fresh broken. 



3. Gre?/ Sandstone. — Above the amygdaloid f beds of a yellowish 

 grey sandstone alternate with tuff and claystone, which appear to 

 be intimately connected with some varieties of the amygdaloidal 

 rock. It contains a considerable quantity of scales of silver-white 

 mica, and decomposes into slaty masses. It seems to pass almost 

 imperceptibly into the varieties of claystone to be hereafter de- 

 scril)ed. One variety of this rock has a very remarkable granitic 

 appearance, and does in fact contain all the constituents essential 

 to truc'granite. At the same time, however, it retains the distinc- 

 tive characters of sandstone. 



The relations of this rock to the older rocks is not clearly made 

 out, except at Wormit Bay, where it seems to rest on amygdaloid. 

 It occurs frequently between Wormit Bay and the village of Dun- 

 ning, in Perthshire. It also occurs in the course of the Devon, 

 where it may be seen alternating with the red sandstone, to which 

 in all probability it belongs. 



Its general dip is to the south-cast, and its direction from north- 

 east to south-west. 



4. Limestone. — In a quarry at the base of Park Hill, not far 

 from Bam briech Castle, ij: a saddle-shaped mass of yellowish grey 

 limestone rests between beds of slate-clay and grey sandstone ; and 

 above the newest sandstone there is a bed of greenstone, the upper 



• Tliis place is about half way befween Kinross an:l Abernethy. 



+ Al thf westfrii fxtrcinity of Wurinit Bay. 



\ Hambrierh Castle stands on a proiiioiiiory of red sand^iloiio, wiiirh runs a 

 ibort way into the Tay, from its sou(h( rn bank, about thrcv inilc^ to ilir i-a^lward 

 ofthi-hiitall ki-a-|)orl uf Ncwburgh. irniiu;(liali-ly lo ill- soiitli of llio ca.-lli' the 

 Ochih rikL- very rapidly, and rocrivo diircrciit names. That of Park Hill it 

 appropriated lotbt; hill jjulf way liciwecn Mcwburgh uod litiubriech. 



