NOTES AND QUERIES. 



311 



on one or two points, principally as to the formation to which the sandstone 

 near the Ardwick limestone beds belongs. He could not see what objec- 

 tion there should be to insert a little strip of lower red sandstone of the 

 Permian formation there. This he has done himself in the map published 

 by the Geological Survey, and he thought the reasons for doing so out- 

 weighed those for the opposite course. He also considered that the Irwell 

 Valley fault ought to be continued to the Mersey, at Heaton Mersey ; 

 and the eastern boundary fault of the Manchester coal-field to Stockport. 

 Also, that there was a second bed of boulder clay lying above the sand and 

 gravel ; but in his general views on the subject of the drift, he fully con- 

 curred with Mr. Binney. 



NOTES AND QTJEEIES. 



The Granite Rocks of Donegal is a subject that has been taken up in 

 a determinate and able manner by Mr. Robert H. Scott, the Secretary of 

 the Geological Society of Dublin, and several valuable papers on it have 

 been read by him, and have been published in the ' Dublin Quarterly 

 Journal of Science.' He points out the very remarkable fact that the so- 

 called igneous rocks of Innishowen are contemporaneous with the sedi- 

 mentary rocks of that district. "In the north of Innishowen," he says, 

 " the chief rocks observed were grits, crystalline limestone, mica slate, and 

 a variety of greenstones and syenites, passing by insensible gradations into 

 the two distinct types of syenite of Ardara and Horn Head. The whole 

 of these rocks are contorted considerably about Culdaff, and from that 

 to Maiin Head they exhibit a consecutive section, of which the dips increase 

 as you go westward, the beds being nearly horizontal (dip 20° to 25° E.) 

 at Culdaff and along the shore towards Glengad Head, and consisting of 

 grits, inters tratified with igneous rocks. ... It is very remarkable that the 

 igneous rocks, to which allusion has already been made, as being found in 

 great abundance in the county, in Innishowen, are undoubtedly contem- 

 poraneous with the sedimentary rocks of the district. This fact is ob- 

 servable along the coast, but it is noticeable in the most striking manner 

 between Bunerana and Carndonagh, about five miles from the former 

 place, — the whole of the hills lying between Slieve Snaght and the Raghtin 

 mountains being composed of alternating beds of quartz rock and syenite, 

 dipping at a low angle to the eastward. This is beautifully exhibited in 

 the mountain of Binmore or the King of the Mintiaghs, lying in the dis- 

 trict called the Barr of Inch, close to the Mintiagh lakes. , 5 

 This hill, with its consort, the Queen, form a very strik- l'° i 



ing feature in the landscape, when seen from any point . !« j 

 in the northern part of the county. . . . These hills and \ j j 

 the mountain Bulbin are terraced like the trap hills X }' 



of Antrim and the coast of Argyllshire ; but on a close N 

 examination, it is found that, though the conclusions 

 drawn from the terraced form are further borne out by / 

 the fact that all the beds are columnar, yet they consist ■'' o ^ y\ l\ 

 of alternate beds of quartz rock and syenite, as before \ i? \ 



described. The columnar structure of the former is ! 

 due to the simultaneous development of three series Joints in King of the 

 of joints, inclined to each other at angles approaching Mintiaghs. 

 those of a regular hexagon. These joints are all of them traceable in 

 other parts of the county ; but it is only here that they assume a deve- 

 lopment of such equal importance. 



