Reports & Proceedings — Geological Society of London. 331 



particular map had been lost for over eighty years. Smith's finest 

 piece of work, his map of the Blackness district, dated 1832, 

 apparently had not been seen by any worker since its publication, 

 and the lecturer explained how he had recently been able to trace 

 two copies. One of them, which was exhibited, he presented to the 

 Society. 



In the Society's possession also is an extensive and valuable 

 collection of the maps of Greenough, both published and in 

 manuscript. Among an extraordinary series of coloured maps of 

 England and Wales, and of the British Isles, issued during the 

 middle of the nineteenth century, those by Arrowsmith, Murchison, 

 Walker, Eamsay, Eavenstein, Knipe, Phillips, and Johnston are 

 especially noteworthy. 



The Society's collection includes geological maps of Scotland and 

 Ireland, some of great value and historical interest. Of Scotland, 

 the remarkable series by MacCulloch, published and in manuscript, 

 shows that the collection is by far the finest as regards early maps 

 dealing with the geology of the country. A manuscript map of 

 Scotland by decker is dated 1808 (earlier than Smith's large map of 

 England and Wales), and is undoubtedly the oldest. Among the 

 maps of Ireland there is the fine series by Griffith, which includes 

 a few examples not known by Judd or other writers on the subject. 



As examples of privately published maps, those by Sanders of the 

 Bristol Coalfield, Jordan's London District, and Elias Hall's 

 Lancashire area were described. The lecturer concluded by referring 

 to a catalogue of geological maps (other than the Geological Survey 

 publications) which he had in course of preparation. This already 

 contained details of approximately 3,000 maps. 



June 6, 1917.— Dr. Alfred Harker, F.R.S., President, in the Chair. 



The following communications were read : — 



1. "On the Geology of the Old Radnor District, with special 

 reference to an Algal Development in the Woolhope Limestone." 

 By Edmund Johnston Garwood, Sc.D., F.R.S., E.G.S., and Edith 

 Goodyear, B.Sc. 



The district comprises an inlier of Archaean grits and Woolhope 

 Limestone forming an elongated dome bounded by Wenlock Shale. 

 It was regarded by Murchison and the Geological Survey as 

 consisting of Hayhill Sandstone succeeded conformably by Woolhope 

 Limestone, and they attributed the unfossiliferous character of the 

 sandstone and the abnormal facies of the limestone to alteration 

 by igneous intrusious. Dr. Callaway, in 1900, first suggested that 

 the so-called " Mayhill Sandstone" was of Archaean age, and 

 recorded an unconformity at the base of the limestone. The authors 

 confirm Callaway's views, and give evidence for correlating these 

 Archaean rocks with Professor Lapworth's " Bayston Group " of the 

 Longmyndian. The unconformable relation of the limestone to the 

 Archaean is established in several portions of the district; while 

 a study of the Trilobite and Brachiopod fauna of the limestone and 

 included shale confirms the Wenlock age of the deposit. The most 

 interesting fact brought out by a study of the limestone is the 



