SCIENTIFIC SURVEY. 39]^ 



viz : \ipon the more southern of the St. John ponds, north-west 

 from Moosehead lake. Without doubt there are many in the State 

 yet to be brought to light. 



This makes an addition of seventeen horsebacks brought to light 

 since the publication of the first report. In other words the num- 

 ber of known horsebacks in Maine has been doubled the past 

 season. 



We hope that geologists will pay more attention hereafter to the 

 investigation of those curious gravel ridges. We doubt not that 

 they will be found common over the northern border of the United 

 States. We were surprised and delighted to see two beautiful ex- 

 amples of them in Lower Canada the present winter. One is in 

 St. Flavien near Quebec, composed of coarse materials. The other 

 lay partly in Acton and partly in Wickham, and is composed of 

 finer materials. A section of it is precisely like our ideal section 

 of the Maine ridges. Both these Canadian examples are situated 

 in the flat country adjoining the river St. Lawrence, and both run 

 N. E. and S. W. Both of them, also, are several miles long. Their 

 general characters agree perfectly with those of the Maine exam- 

 ples. 



We do not yet feel satisfied about the true theory of the forma- 

 tion of horsebacks. We could not but be surprised, however, 

 when on Moosehead lake, to see how very similar they are to such 

 islands as Sandbar, Snake and Hogback. A section of the first ia 

 like that of the horsebacks. These islands are very long and nar- 

 row, being composed of coarse and fine gravel. It would not be 

 strange if some of the horsebacks were formed like Sandbar island, 

 which seems to have been deposited by currents, either with or 

 without the assistance of ice. Sandbar island must have been 

 formed in a past period, when Moosehead lake stood at the level 

 of the terraces which may often be met with at the mouths of its 

 tributary streams. Snake island would appear to be one that is 

 forming at the present level of the lake. 



Sea Beaches. 

 A single example of the more elevated stratified gravelly banks 

 of assorted gravel and sand, which have been referred by us to the 

 action of the waves of an old ocean, was pointed out last year. 

 We would suggest a few others this year, without having had time 

 to observe carefully their altitudes or relations to the surrounding 



