288 LLANDOVERY AND ASSOCIATED ROCKS OF CONWAY. [May 1 896, 



VI. General Conclusions. 



Prom the facts brought forward in the present paper it is evident 

 that rocks of Llandovery age do occur in Worth Wales, and hence that 

 the stratigraphical break in that region between the Silurian and 

 Ordovician rocks is, at any rate, far less actually than has hitherto 

 been supposed. 



The type of Llandovery rocks developed at Conway is more closely 

 related to that of Southern Scotland and Northern England than to 

 that of the typical Welsh Borderland area, and it is interesting to 

 observe that here, at any rate, deep-water conditions prevailed from 

 Upper Llandovery to Wenlock times. 



With regard to the Tarannon Shales, Wenlock Shales, and 

 Denbighshire Grits and Flags, they differ in no essential respect 

 from those found in the Dee Valley, which have been recently shown 

 (Lake, Quart. Journ. Geol. Soc. vol. li. 1895, op. cit.) to be the 

 normal type, and therefore require no further comment. 



Our best thanks are due to Mr. J. E. Marr, E.R.S., and Prof. 

 Charles Lapworth, F.R.S., for much kind help and assistance in our 

 work. 



Discussion. 



The President said that the Authors of this paper had made 

 an exhaustive survey of a limited area, collecting the fossils and 

 correlating with care the graptolites from each horizon. Such work 

 deserved the Society's praise, as following the example of Prof. Lap- 

 worth and other careful workers. Such accurate field-work, coupled 

 with careful palseontological results, was of the greatest value. 



Dr. Hicks said that he had listened with much interest to the 

 paper, and he hoped the Authors would continue their researches 

 into other areas in North Wales, for it is highly important that the 

 fossil-zones in the beds forming the base of the Silurian in that area 

 should be clearly defined. He had not examined the sections referred 

 to by the Authors, but some years ago he found that the sandstones 

 on the eastern side of the Conway valley (towards Llanrwst) con- 

 tained Nematophycus and other fossils characteristic of the Pen-y-glog 

 Beds near Corwen. He would have liked to hear whether the 

 Authors considered that the deep-water beds of Tipper Llandovery 

 age at Conway rested directly on the Bala Beds, and whether there 

 was an entire absence of the beds near Bala classed by Mr. Ruddy 

 as Lower Llandovery. 



Mr. W. W. Watts congratulated the Authors on a most admirable 

 piece of work. He pointed out how the Upper Llandovery rocks had 

 been gradually recognized and extended. There was no gap between 

 those of Shropshire and of Conway, for the rocks had been recognized 

 on the Breiddens, near Meifod in Montgomeryshire, and in the 

 Berwyns. There appeared to be no evidence of conformity between 

 the Ordovician and Silurian rocks in the Conway district, in spite 

 of the fact that somewhat deep-sea beds had been found there. 

 He hoped that the Authors would recognize the Monograptus 

 colonus- and M. leintwardinensis-ke&s in the Denbighshire Grit. 



