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PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Feb. 5, 



to the great mass of the shelly sandstones of Saugh Hill, Mulloch 

 Hill, &c. 



If I were to draw my inferences either from the original Silurian 

 region or from the Bohemian development of rocks of the same age, 

 I should not have hesitated to place these flagstones in the lower part 

 of the Upper Silurian division. But here again, as in relation to 

 other fossils already alluded to, I am reminded that forms of the 

 genus Cyrtoceras have also been found by the Government geo- 

 logists very deep in the Lower Silurian ; thus linking the whole series 

 together by a community of zoological types. 



Not relying, therefore, on such fossil evidences for a point of detail, 

 which after all is of no great import, we have still, I think, fair evi- 

 dences of superposition. From Shalloch Mill to Ardwell and Ard- 

 millan (see fig. 3), the strata are either vertical or so slightly inclined 

 to the S.S.E. that I came to the conclusion, that just as the last 

 visible pebble-bed in the Saugh Hill ascending section dipped S.S.E. 

 and thus seemed to pass under flagstones, so do the Shalloch and 

 * Kellie Bock ' scars (2) stand in the same relation to the orthoce- 

 ratite-flagstones (1). It seemed to me unquestionable, that the very 

 beds in which the Orthoceratites occurred on the shore, were by 

 their strike traceable into Piedmont Glen, where they are seen in a 

 highly inclined, broken condition, and in parts mineralized. In pro- 

 ceeding along the shore, these flagstones are also seen to be broken, 

 dislocated, and incurvated in every possible manner, two examples 

 of which I offer in figs. 5 and 6. Traversed here and there by 

 small trap-dykes, these flagstones acquire, however, a steady dip to 

 the N.N.W. as they approach the bold headlands of conglomerate 

 and igneous rock which range down to the bluff coast from the 

 grey hill of Ardmillan and Shill Hill. The rocks cut through in 

 constructing the striking coast-road which leads from Girvan to 

 Ballantrae consist, at the headland called Kennedy's Pass, of by 

 far the finest example of coarse Silurian conglomerates which I 

 have met with in any part of the world ; and there they dip most 

 unequivocally to the N.N.W. under the orthoceratite-flags and 

 schists at an angle of 40°, as represented (2*) in fig. 3. This section 

 coming, therefore, with a reversed dip in corroboration of that of 

 Saugh Hill, my belief is, that the flagstones and schists occupy a dis- 

 located, contorted, and broken trough, supported on the one side by 

 the pebble-beds, conglomerates, and shelly sandstones of Saugh Hill, 

 and their coast equivalents of Shalloch and Kellie Bock, and on the 

 other by the coarser conglomerate of Ardmillan Hill and Kennedy's 

 Pass on the coast, and by the limestone and schist (3, fig. 2) in the 

 interior. 



This spot must not, however, be quitted without a description of 

 its very powerful and striking conglomerate. All the materials of 

 this conglomerate are rounded and waterworn, and, according to Pro- 

 fessor Jameson, some of the pebbles which he had seen many years 

 ago seem to indent each other ; an observation, I may remark, which 

 agrees with one recently made by M. de Verneuil in examining the 

 conglomerates of the Devonian or Old Bed Sandstone age in the 

 Cantab rian range of Spain. Professor Nicol and myself distinguished 



