94 REPORT-^ISSS. 



could in most instances determine the group by an examination of the limestone 

 quarries. In fact, as limestone strata often afforded the key to the fossiliferous 

 groups, so limestone, in a great measure, enabled the worker out of primary forma- 

 tions to ascertain his lithological place and position. In submitting the preceding 

 arrangements, he (Mr. Page) was perhaps advancing nothing new to many members 

 of the Section; still he was aware that much doubt and error prevailed respecting 

 the relations of the stratified system in Scotland, and by thus attempting their 

 grouping and subdivision, it would facilitate comparison with other regions, and 

 especially with continental Europe and North America, where so many eminent 

 geologists were working out with admirable precision and in detail the rock arrange- 

 ments of their respective localities. He had endeavoured to be as explicit as 

 the time allowed for such an outline would permit, and would venture to predict 

 that the time was not far distant, when the ancient rocks of Scotland, notwith- 

 standing the obscurity of the subject and the difficulty of the research, would be 

 as minutely grouped and as well understood, as the younger, the more attractive, and 

 the more easily deciphered fossiliferous secondaries of England. No doubt, different 

 geologists would attach different degrees of value to these attempted subdivisions ; 

 but in a science like geology, where as yet so much was temporary and provisional, 

 and where the height to be ascended was so steep and arduous, the more notches in 

 the cliff, the more easy the ascent ; and if once the path were familiar and known, we 

 could dispense with many of the intermediate notches, and make our steps the fewer 

 and more comprehensive. 



Remarks on certain Trap Dykes iii Arran- 

 By Professor Phillips, M.A., F.R.S. 



The author exhibited maps and sections of the trap dykes between Brodich Bay 

 and Lamlash Bay — for the purpose of showing the existence of a certain law regard- 

 ing the direction of these dykes, as compared with the strata of the Red Sandstone 

 strata, and the axes of subterranean movement in Arran. The investigation, founded 

 on two sets of careful observations, in the years 1826 and 1855, on forty-four dykes, 

 ■which were separately described for the purpose, proved the dykes to be assembled 

 in two principal systems or groups, both included in arcs of 90°, so as to produce 

 alternating quadrants of -f- and — , capable of combination into one general re- 

 sultant. The dykes are not generally accompanied by vertical displacement; the 

 sandstones on their borders are usually bleached and indurated so as to run in high 

 crests, above the frequently excavated course of the dyke. Many special phaeno- 

 mena were pointed out in regard to the " Claystone," " Pitchstone," and " Green- 

 stone" dykes, of this and other parts of Arran, as a preliminary to an excursion on 

 the coast after the conclusion of the meeting. 



Note on a recent Geological Survey of the Region between Constantinople and 

 JSroussa, in Asia Minor, in search of Coal. By H. Poole. Com- 

 municated by Sir R. I. Murchison, ivith the permission of the Earl of 

 Clarendon. 



Sir Roderick Murchison briefly explained, that in consequence of reports of the 

 existence of coal on the south side of the Gulf of Nicomedia in the Sea of Marmora, 

 he had recommended Mr. H. Poole to Her Majesty's Government as a surveyor 

 capable of determining the nature and value of the combustible. The Earl of Claren- 

 don had in consequence sent out that gentleman, who had ascertained that the so- 

 called coaZ was a poor lignite only, and probably of tertiary age; and that thus the hope 

 of the old coal of Eregli (Heraclea) being continuous to or repeated in the Gulf of 

 Nicomedia so near to Constantinople was dispelled. 



On th0 Geology of (he J}istrict of Great and Little Ormeshead, Nerlh Wales, 

 By John Price, B.A. 



