B. M. Brown — Clays of the Boston Basin. 445 



Art. XLIII. — The Clays of the Boston Basin ;'^ by Egbert 

 Marshall Brown. 



The problem of the correlation of the clays of ]^ew England 

 has never been solved, l^umerons papers have been published, 

 in which various clay beds have been described and in part dis- 

 cussed. Some of the writers have ventured to correlate the 

 clays of neighboring sections. No one has yet undertaken the 

 solution of the entire problem. Not enough light has been cast 

 upon the subject for a general discussion. The isolation of 

 elay beds in the same neighborhood with no evidence to show 

 whether they are parts of the same deposit or disconnected 

 deposits of the same time or unrelated beds, offers little of 

 interest. Similarity of clay itself cannot be taken as good data 

 for correlation, unless by chance some unique peculiarity of 

 composition is discovered. Ordinarily, the zest to further search 

 is furnished the student of clays by the constant excavations 

 that are made in the streets for the laying of pipes, the opening 

 of new clay pits, the extension of the old, and the removal of 

 the cover of the clay for various purposes. All new exposures 

 which furnish interesting evidence in any direction should be 

 recorded. By the accumulation of such evidence, it is believed 

 that in time a correlation of the clays of New England and 

 beyond may be safely attempted. For this reason, the writer 

 of this article desires to place on record some of the results of 

 this field study on the clays about Boston, with a few observa- 

 tions that arose during the process of the investigations. 



Field Work. — Near Chelsea Street, between the cities of 

 Everett and Chelsea, Massachusetts, extensive excavations, 

 during the fall of 1901, revealed the clays. A hill, drumlin- 

 like in appearance, of no great height, and half a mile long, 

 with a trend a little south of east, parallel to the drumlins 

 of the neighborhood, was in part removed. An almost com- 

 plete cross section of the hill was exposed. The core of the hill 

 is an igneous rock (fig. 1). The rock does not extend to the 

 southern slope, however. Here a clay and sand interior was 

 found. Both clay and rock was capped by a thin layer of till. 

 The relation of the clay to the rock was unknown, as neither 

 the quarrying of the rock to the north nor the removal of the 

 clays to the south showed the contact. The first appearance of 

 the south end of the hill in the process of removal of the 

 material showed an anticline in the clay. The stratification of 

 the beds was emphasized by the interlamination of thin layers 



* This paper is a part of a thesis presented in the course on Glacial 

 Geology at Harvard College, under Prof. J. B. Woodworth. 



