GLACIO-AQUEOUS ACTIOiN IN NORTH AMERICA. 195 



that detritus has been driven down the valleys occupied by rivers, 

 we find, also, that as a whole, it has obeyed that force which has 

 carried our drift southeasterly. It would not be strange, if some 

 cases should be found, where the force urging it along particular 

 valleys should have carried it in almost an opposite direction : 

 though I have never met with such a case, and presume, if it 

 occur, it is probably quite limited. 



Since printing my Report on the Geology of Massachusetts, I 

 have met with a few examples of the peculiar moraines above 

 described, in the eastern part of that State, which deserve a short 

 notice. 



The town of Newburyport appears to be built entirely upon a 

 ridge of drift, which has been more or less modified. High Street 

 runs along the highest part of the ridge ; and if wc proceed west- 

 erly, we shall follow the ridge for three or four miles. At that 

 distance * we meet with a good example of those peculiar tortu- 

 ous ridges, and in'egular tumuli with deep depressions, which 

 have been described. In the depressions I noticed one or two 

 ponds. A few of the same ridges and tumuli occur within and 

 around the cemetery at the head of High Street in Newburyport. 

 The cemetery occupies a tumulus, as is the case at Plymouth, 

 North Adams, and some other places in Massachusetts. A pond 

 also occupies a depression at the head of High Street. It ought 

 likewise to be mentioned, that the materials of the moraines in 

 the town, are considerably coarser than those three miles west, 

 where they are chiefly coarse sand. 



I was conducted to another spot where these peculiar moraines 

 occur, by Dr. Robinson of Salem. It lies three miles southeast 

 of that city, on the road to Marblehead, and just within the limits 

 of the latter place, as we rise a high rocky hill. Against that hill, 

 a few rods to the west of the road, and in a spot where we should 

 hardly look for them, we find several of these moraines, with very 

 steep sides and deep cavities between them. A pond occupies 

 one of the depressions. The drift here is composed mostly of 

 gravel ; although rather more coated with grass than is usual. 



* I am indebted to IMr. Anthony Jones, of Newburj-port, for eouducting- me to that spot. 



