Brief Notices. 523 



of Agriculture and Technical Instruction, issued in 1908 a special 

 colour-printed map and memoir of the geology of the country around 

 Londonderry, the work of Messrs. S. B. Wilkinson, A. McHenry, 

 J. R. Kilroe, and H. J, Seymour, under the direction of Professor' 

 G. A. J. Cole. In mapping the Drifts it was found necessary also to 

 map (on the six-inch scale) the Igneous, Metamorphic, and Lower 

 Carboniferous rocks. The memoir is well illustrated with photographic 

 plates and text-figures, and contains much of scientific interest as well 

 as accounts of soils, water-supply, and other economic matters. 



3. The Queenslamd Geological Survey has issued a second report 

 on "The Etheridge Goldfield", by Mr. W. E. Cameron (publication 

 No. 219, 1909). This goldfield occupies an area of more than 

 13,000 square miles, the centre of the field being about 200 miles 

 south-west of Cairns. The rocks consist of granite, quartz-porphyry, 

 and diorite, together with altered sedimentary rocks, comprising 

 massive white quartzites, schists, and slates, with which are associated 

 numerous mineral veins carrying gold, silver, lead, and copper. The 

 gold-bearing quartz veins occur, however, mainly in the granite, and 

 the yearly average yield of reef gold since 1900 has been 9000 ounces. 



4. Permian Footprints. — In an essay on "British Permian Foot- 

 prints" (Mem. Manchester Lit. and Phil. Soc, 1909, liii), Mr. George 

 Hickling endeavours to show that footprints may be used to distinguish 

 Permian from Triassic deposits. Judging by the footprints from 

 definite Permian strata at Mansfield and Penrith, he would group 

 the footprint-bearing rocks of Corncockle Muir and other localities 

 in Dumfriesshire, and those of Cummingstone in Elgin, as Permian. 



5. Erosive Action of Snowfall. — In an essay entitled "Physio- 

 graphical Notes, No. 1 " [Geographical Journal, July, 1909), Mr. G. W. 

 Lamplugh discusses the erosive conditions resulting from snowfall. He 

 has been impressed by the great discrepancy between the efl^^ects of 

 erosion on contiguous tracts in various parts of Ireland and in the north 

 of England, where drumlins of boulder-claj', esher-ridges ;ind kame- 

 mounds of sand and gravel, and moraines of incoherent rubble, show 

 little or no evidence of sub^rial denudation, while neighbouring 

 streams have cut trenches through a great thickness of drift into the 

 underlying bed-rock. In explanation he has been led to conclude 

 that there was much winter precipitation of snow during the waning 

 phases of the Glacial epoch, and that during the warmer season the 

 gradual melting of the snow caused a gentle flow of water over the 

 slopes, but led to powerful torrential action along the stream-channels. 

 This explanation is well worthy of consideration, apart from other 

 evidence that would apply in some localities, of erosion due to flood- 

 waters resulting from the melting of ice in earlier times, or of the 

 re-excavation of ancient buried channels. 



6. Dew-Ponds. — Mr. E. A. Martin has further dealt with the 

 subject of Dew-Ponds {Geographical Journal, August, 1909), and 

 gives some analyses of the waters. The pi-esence of sodium chloride 

 is interesting as an indication that much of the aqueous vapour came 

 from the sea. In the course of discussion Dr. H. R. Mill referred to 



