JSLA. GEOLOGY. 1 25 1 



be found in the superior hardness and durability of this 

 substance ; thus rendering it more capable of resisting the 

 actions by which these fragments were produced. 



In attempting to elucidate the history of these lime- 

 stones and that of the accompanying conglomerates, by 

 the analogous observations to which I alluded, light 

 will be thrown not only on the different points here 

 brought into comparison, but a very interesting commu- 

 nity of strata, will be indicated ; although perhaps actually 

 interrupted and again renewed, as is not unusual among 

 the primary strata.* 



In the preceding remarks it has been shown, that the 

 extreme limits of the lines of direction in the strata of 

 the schistose islands already described, lay between N. J E. 

 and N. E. by N. 5 and in the first group it was further 

 shown, that all the strata were regulated by the one 

 or the other of these bearings. The directions in Jura 

 and Isla have not been ascertained with the same accu- 

 racy, yet they have still been found included within the 

 above named limits. It has also been remarked that 

 the apparent point of flexure in the strata of Jura, took 

 place near its northern extremity, where it is indicated 

 by the outlines of the coast ; the northernmost portions 

 of that island lying on the N. J E. rhumb line, while 

 the southern, even to the extremity of Isla, tended consi- 

 derably more to the eastward. If from Lossit hill a line 

 be drawn to Garveloch conformable to these directions, 

 a correspondence will be found to exist between the 

 bearings of the strata in these two remote places, as 

 accurate as could be expected from the nature of the 

 maps and the known deviations to which such strata 

 are liable. This coincidence is very remarkable, and 

 appears in itself almost demonstrative of the identity 

 of the beds of Garveloch with those of Lossit hill. But a 

 stronger proof of it seems to be afforded by the simi- 



* Sec the general Map. 



