Geology and Mineralogy. 1 97 



the clay products of Iowa stand second in value only to the out- 

 put of coal. The survey is also collecting data relative to the 

 artesian waters in Iowa, and plans to publish a report on the 

 same. The U. S. Survey has completed the topographical work 

 in northeastern Iowa, so that the state survey will now work out 

 the details of geology in that section. An investigation is in pro- 

 gress regarding the coals of Iowa, their occurrence, physical and 

 chemical characteristics, geological and geographical relations. 



3. Glaciation in South Africa. — At the October meeting of 

 the Geological Society of South Africa, Mr. M. E. Frames 

 describes the geology of the Amsterdam Valley. Part of the 

 village of Amsterdam is built on a glacial moraine of undoubted 

 Dwyka structure and age. As had been shown before, a direc- 

 tion of glaciation which resulted in the deposition of the Dwyka 

 is proved to have been from the north. This view has recently 

 received support from the fact that a characteristic porphyritic 

 rock which is found in the conglomerate at Amsterdam has been 

 discovered in situ forty miles to the north. A large outcrop of 

 this rock has been discovered on Bonnie Braes farm near Oshoek. 



4. TJeber Untersllur in Venezuela ; von Dr. Fr. Drevermann. 

 Neues Jahrb. f. Min., Geol. u. Pal., 1904, pp. 91-93, pi. x.— 

 This little paper is of great interest in that it proves the occur- 

 rence of lower Paleozoic deposits on the north side of the Vene- 

 zuelau-North-Brazilian shield. Engineer Klein, in traveling from 

 Caracas over Valencia to Puerto Cabello, collected a few fossils 

 which Dr. Drevermann thinks are indicative of Lower Silurian 

 aore. These specimens are Calymmene senaria like those from 

 Cincinnati, Ohio, and Orthoceras cf. olorus Hall. As no Ordo- 

 vician formations are known in northern South America the 

 reviewer raised the question — Are these fossils probably of Silu- 

 rian age ? With this in view he addressed the author of the 

 present paper, under date of August 3, 1904, as follows: "The 

 Calymmene is nearer to C. niagarensis than to C. senaria (= C. 

 callieephala). ... As for Orthoceras cf. Vblorus it may be 

 one of several of our Niagaran annulated forms. Its size is so 

 large that I think it rather a Niagaran species. 



" On the other hand, in Brazil on the south side of the old land 

 mass there is good Upper Silurian, which as you know was 

 described by Clarke. All in all I feel that the Venezuela fossils 

 are of Upper Silurian age." On October 25 last, Drevermann 

 replied as follows : " I have had another opportunity to compare 

 the Calymmene of Venezuela with the North American material 

 kindty sent me by you. An identity with C. niagarensis I can- 

 not agree to in spite of the extraordinary similarity heightened 

 by the fact that both examples are preserved in dolomite. The 

 lower lobe of the glabella of the Venezuelan specimen is much 

 larger than in C. niagarensis and the latter in this respect 

 reminds one of C callieephala (respectively C. senaria). The 

 head of C. niagarensis is also considerabty more arched. On 

 the other hand, the South American example agrees with C. 



