66 The Ohio Naturalist. [Vol. VII, No. 4, 



As previously stated they are also to be found more or less 

 abundantl}- in the Lowlands of Scotland and in Ireland. In the 

 former country thev usually rise abruptly from the till to a height 

 of 20 to 30 feet and \vith a width of 100 to 400 feet. Those in 

 the latter country are remarkable for frequently being dotted 

 over wdth large erratics. 



Turning to our own country we find their greatest develop- 

 ment in Maine. In fact these are second to none unless it be to 

 those of Sweden. Not only are they the greatest but more pages 

 of minute description and more hypotehses to explain their for- 

 mation have been written than of those in any other locality. 

 Some fift}' systems have been described by Stone. A few of 

 these systems attain a length of 100 miles and some 125 miles. 

 When we .consider that each of these systems comprises the sed- 

 iments deposited by a single glacial river with its tributary and 

 delta branches and that they frequently consist of a number of 

 short ridges we see the magnitude of their development. 



Eskers are much less strikingly developed in other New Eng- 

 land states, in New York, Pennsylvania, Ohio, Indiana, Illinois 

 and Wisconsin. These are mostly short gravel ridges. Some- 

 times they can be seen to comprise a S3'stem. 



For Ohio these have been worked out in some detail. Lev- 

 erett has described, in Monograph XLI of the United States 

 Geological Survey, eleven such gravel ridges as follows: 



The Circleville Esker, Pickaway Co., pp. 429-431. 



The esker in Fairfield Township, Huron Co., p. 597. 



The Hartland Esker, Huron Co., pp. 615-617. 



The Leesville Esker, Crawford Co., p. 542. 



The esker near Norwalk, Huron Co., pp. 5S7-5S8. 



The Pickerington Esker, Fairfield Co., pp. 428-429. 



The Radnor Esker, Delaw'are-Marion Cos., pp. 540-541. 



The Richland Esker, Logan Co., pp. 489-490. 



The Richwood Esker, Union Co., p. 540. 



The esker near Springboro, Warren Co., pp. 



oo2— OOO. 



The Taylor Creek Esker, Hardin Co., pp. 538-540. 

 All of these are 3 miles or less in length, except the Circleville 

 and Pickerington eskers which are 9 and 5 miles respectively. 



The Columbus Esker. 



In the northeastern part of the city of Columbus is a ridge, 

 the location of which has been known for a long time, but whose 

 structure and composition were, probably, not recognised until 

 last Spring, when it was the writer's good fortune to detect it. 

 Workmen had excavated a ditch across its northern end -for a 

 water main, which exposed its alternate strata of sand and gravel 

 to view. This gravel ridge probably ought to be described be- 

 cause of its convenient location, espccailly to the Ohio State 



