858 



SCIENCE 



[N. S. Vol. XXXVIII. No. 989 



rounded by disease, apparently from two con- 

 fluent lesions, one of which started about mid- 

 way between cuts 4 and 5, but on the opposite 

 side of the limb, while the other started near 

 cut 5 and on the same side of the limb. Judg- 

 ing only from the size of these lesions, they 

 must have originated soon after the inocula- 

 tions were made. There was no evidence that 

 any infection had started at cut 5. Cut 6 was 

 uninfected. Cuts 7 and 8 showed sunken 

 areas but no fans, pustules, nor other symp- 

 toms of the disease. Cut 9 had developed a 

 girdling lesion 7 inches long with very many 

 pustules. Cut 10 had developed a lesion 4A 

 inches long and 3 inches wide. Cuts 11, 12, 

 13 and 14 were uninfected. Cuts 15 and 16 

 had produced confluent girdling lesions aggre- 

 gating 11 inches in length. This probably 

 indicated that each cut had produced a lesion 

 about 6 inches in length, as the cuts were 

 about 5 inches apart. Cuts 17 and 18 were 

 uninfected. 



The results of these inoculations may briefly 

 be summarized as follows: 

 2 inoculations from typical canker on bark, 



both successful. 

 2 inoculations from pustules on nut, both 



successful. 

 2 inoculations from mycelium on nut, one 



successful. 

 10 checks cut with sterile knife, none infected. 

 2 checks cut with contaminated knife, none 



infected. 



These inoculations indicate that the dis- 

 ease was present on or in the nuts and burs 

 collected. Although the latter were not used 

 in the inoculations, the nuts and burs were 

 covered with the same fungus, judging only 

 from an examination with a hand lens; and, 

 moreover, the nuts and burs were in contact 

 when collected. 



Perhaps nuts infected in this manner are 

 not likely often to reach the market, and pre- 

 sumably would be unsalable either for seed 

 purposes or for eating if they did reach it. 

 In the latter case an additional source of 

 danger would be created by discarding the 

 diseased nuts, perhaps in a new locality far 

 distant from the place where they were grown. 



In any event, the possibility of the disease at 

 times being disseminated through great dis- 

 tances in this manner can not be overlooked 

 in summing up the evidence bearing on this 

 phase of investigation. 



J. Franklin Collins 

 Office of Investigation in Forest 

 Pathology, Bureau of Plant Industry, 

 Providence, E. I., 

 October 20, 1913 



INTERGLACIAL MOLLUSKS from south DAKOTA 



Mr. W. H. Over, of the University of South 

 Dakota Museum, recently submitted for 

 study a most interesting collection of inter- 

 glacial mollusks. The material, consisting of 

 wood, cones, shells, etc., in muck, were found 

 in a well 20 feet below the surface, two or 

 three miles north of Grandview, in Douglas 

 County, South Dakota. 



Professor James E. Todd thus refers to 

 this material:'- 



An Ancient TamaracTc Swamp. — Near Grand- 

 view, in the southeast quarter of sec. 33, T. 100, 

 E. 64, were found traces of more recent occupa- 

 tion of the region by trees. In a well which had 

 been dug on the edge of a basin near a branch of 

 Andes Creek at the depth of 20 feet was found a 

 layer of muck several inches in thickness, in which 

 were pieces of wood with numerous fresh-water 

 shells of nearly a dozen species. But the most re- 

 markable thing was the stem of a hemlock or 

 tamarack about 10 inches in diameter lying across 

 the well, and in the muck were numerous cones 

 evidently of the same species. Overlying this trace 

 of a tamarack swamp was mud of various colors 

 and consistency, evidently washed from the sur- 

 rounding hillsides. That it should be so deeply 

 buried was chiefly explained by its connection with 

 the channel of Andes Creek. This was conclusive 

 evidence that the region had been occupied more 

 or less by timber since the ice had covered the re- 

 gion, possibly while the second moraine was in 

 process of formation. Similar finds are reported 

 from wells several miles west of that place. 



The overlying till here is Wisconsin, which 

 varies greatly in thickness. The surface is 

 yellow clay underlain by blue clay. The 



1 Bull. 158, U. S. Geol. Survey, p. 121, 1899. 



