736 



SCIENCE. 



[N. S. Vol. VIII. No. 204. 



tain localities the same drift is present on 

 both sides of the escarpment, passing over 

 the interruption, and in other places the blulf 

 niaiks the boundary between two glacial 

 formations. Whatever did cause the es- 

 carpments was local ; for they are limited 

 in extent, and besides them no others with 

 similar alignment exist reasonably near. 

 The only methods ordinarily found are the 

 erosion of sedimentary strata of various re- 

 sistances, and faulting. The geology of the 

 region is that of an old-land surface, of 

 complex structure, composed of very an- 

 cient sediments and crystallines. This 

 could not possibly give such an escarpment 

 by simple erosion. 



The field evidence, however, leads di- 

 rectly to faulting as the ultimate cause of 

 the present topography. Here the physiog- 

 rapher must turn to the geologist for help. 

 But having received his answer, certain 

 problems of erosion are thrust upon him ; 

 and he must decide whether the faulting is 

 recent, and if not, its age and the subse- 

 quent history of the surface. These I have 

 not found treated in the literature of the 

 country, nor more than hinted at in conver- 

 sation with Continental geologists who are 

 acquainted with the localities. 



To the south of the escarpments the rocks 

 are Cambrian, Cambro-Silurian and Silurian 

 sediments, with some outcrops of the pre- 

 Cambrian crystallines close to the fault. 

 To the north are mainly crystallines, with 

 two outcrops of Silurian close to the bluff. 

 In most places where the escarpments are 

 not accompanied by a waterway the sur- 

 face deposits change abruptly. In other 

 instances no change takes place. 



From the physiographic standpoint, then, 

 it appears that the fault is an old one, of 

 unknown date, which brought weaker Si- 

 lurian and Cambrian rocks against the 

 crystallines. The down-throw was to the 

 south, allowing that portion of the sedi- 

 ments which now remains, to drop. Since 



then the country has been reduced to base- 

 level at least once, and probably a number 

 of times ; and any sediments which once 

 extended northward over the crystallines 

 have been eroded. The last cycle of changes 

 has included re-elevation, revival of stream 

 action, and etching out of the present topog- 

 raphy in the less resistant Silurian and 

 Cambrian, giving the appearance of a re- 

 cent fault. 



J. Edmund Woodmaist. 

 Harvahd University. 



LIFE CONDITIONS OF THE OYSTER : N0B3IAL 

 AND- ABNORMAL* 



The Committee are bringing their inves- 

 tigations to an end for the present, and they 

 now state in this final report a series of the 

 conclusions at which they have arrived. 

 The details of the evidence upon which these 

 conclusions are based will appear in a fully- 

 illustrated memoir by Professor Boyce and 

 Professor Herdman, which is nearly ready 

 for publication. A good deal of that evi- 

 dence has, however, been outlined in our 

 former reports (at Ipswich, Liverpool and 

 Toronto), and need not be now repeated. 



Since last year's repoi-t, however, we have 

 gone further into the question of the amount 

 of copper and iron present in different parts 

 of various kinds of oysters, with results 

 which sustain the conclusions we had al- 

 ready arrived at. 



We have also gone more minutely into 

 the question of typhoid-like organisms, 

 their occurrence in shellfish, and the differ- 

 entiation of these from the B. eoli communis 

 on the one hand, and from the true B. 

 * Third and Final Eeport of the Committee of the 

 British Association for the Advancement of Science, 

 consisting of Professor W. A. Herdman (Chairman), 

 Professor E. Boyce (Secretary), Mr. Gr. C. Bourne,' 

 Dr. C. A. Kohn and Professor C. S. Sherrington, ap- 

 pointed to Report on the Elucidation of the Life 

 Conditions of the Oyster under Normal and Abnormal 

 Environment, including the Effect of Sewage Matters 

 and Pathogenic Organisms. ( Drawn up by Professor 

 Herdman, Professor Boyce and Dr. Kohn. ) 



