THE 



GEOLOGICAL MAGAZINE 



NEW SERIES. DECADE V. VOL. III. 



No. IX, — SEPTEMBER, 1906. 



0:RTC3rXl<r JL.JL, Jk-iaTIGXiES, 



I. — The Cakboniferous Succession below the Coal-M'easurks 

 IN North Shropshire, Denbighshire, and Flintshire.' 



By Wheelton Hind, M.D. , B.Sc, F.R.C.S., F.G.S., and John T. Stobbs, F.G.S. 



(With Plates XXI and XXII and five Woodcuts.) 



1. Introduction : Description of the Area Examined. 



IT requires but little imagination to conceive that a very slight 

 subsidence of the country in North Wales lying between the Vale 

 of Clwydd and the estuary of the River Dee would convert it into 

 a peninsula consisting of Carboniferous rocks skirting to the north, and 

 to the east a strip of Silurian ground. The backbone of this peninsula 

 is composed of Lower Carboniferous rocks, forming the high range 

 which starts from the bold cliffs that border the sandy flats of 

 the north shore of Flint from Dyserth to Talacre. Stretching 

 southwards by way of Halkyn Mountain, Moel Findeg, Nerquis 

 Mountain to Minera and Llangollen, this range, in the main, forms 

 an anticline, off whose eastern flanks the higher divisions of tlie 

 Carboniferous system dip in natural sequence towards the River Dee. 

 Rising up from beneath the Vale of Clwydd, the Lower 

 Carboniferous rocks reappear to the west, from the north coast at 

 Colwyn Bay, Colwyn, and Llandulas to south of Ruthin, and in this 



^ This pajierwas read at the Geological Society on April 4th, 1906. Subsequently 

 the Publication Committee notified us, that unless we were prepared to omit all separate 

 lists of fossils, and show their distribution in one large table at the end of the paper, they 

 could not recommend the paper for publication. As the main object of the paper is 

 to work out the paliieoutological succession, and as we establish five life zones, we felt 

 strongly that such a course was unfair to us as authors, that it would render the 

 paper useless to those who went over the ground with it. We could not conceive 

 a satisfactory table which would clearly indicate five zones from some hundreds of 

 species collected from some sixty localities. As copious fossil lists had been published 

 in very recent papers in the Quarterly Journal on Carboniferous zones in other 

 localities, we demurred to the differential treatment and withdrew our paper under 

 the conditions requhed. The paper is in the exact form in which it was read at the 

 Geological Society, with the addition of a discussion on the hoi'izon of the cherts, 

 the interpolation being plainly indicated. 



UECAUE V. — VOL. III. — NO. IX. 25 



