8ir IT. H, Howorth — Surface Geology of N. Europe. 199 



wonderfully continuous. So uniform are they that, as Brongniart 

 jDointed out, the roads in some places, as from Upsala to Wendel, 

 from Enkoping to Nora, from Hubbo to Moklinta, etc., run along 

 their crest. Sometimes they spread and widen out a little, forming 

 nodes like so mauy knots on a cord. Frequently the continuous 

 line is interrupted by a gap or a series of gaps, so that instead of 

 a uniform bank there are a number of huge circular or oval mounds. 

 They consist generally of a main trunk, with a number of small 

 subsidiary lateral branches running into them like the affluents of 

 a river, and sometimes they have satellites attached to them in the 

 shape of eskers and kame-like mounds. They are as sharply 

 marked off from the adjoining plain on either side as a railway 

 embankment is. In some cases, notably in Finland, they do not 

 run in parallel lines, but vary in direction, sometimes even crossing 

 each other, but in Sweden their direction is singularly parallel, as 

 may be seen from the admirable maps published by the Swedish 

 geologists, notably that by Tornebohm. The enormous size and 

 cubical contents of these gigantic mounds can only be appreciated by 

 those who have seen them on the spot and followed them for miles. 



According to Ei-dmann, the well-known Upsala as, which runs 

 from the mouth of the Dalelf to Sodertora, south of Stockholm, is 

 about 200 kilometres long. The as of Koping, as far as it is at 

 present traced, from Nykoping to the Dalelf, is about 240 kilometres 

 in length. The as of Enkoping runs from near Trosa in Suder- 

 mannia to Loos in Helsingland, and is from 300 to 340 kilometres 

 long, while the as of Badelunda, running from Nykoping in Suder- 

 mannia to the parish of Rattvik in Ualecarlia, is about 300 kilometres 

 long. According to Erdmann, the asar west of the watershed 

 between Lake Weneru and Lake Wettern run N.N.E.-S.S.W., while 

 east of that line they run from N.N.W. to S.S.E. 



Erdmann also gives the elevation at which some of the principal 

 asar have been traced. "In Jemteland,N.and N.W. of Storojo, to 1,000 

 or 1,200 feet; in Herjeadal, near Hede, to 1,300 or 1,400 feet; in 

 Dalecarlia, in the parishes of Malung and Idre, to between 1,000 and 

 1,300 feet; in the government of Elfsborg, in Vestrogothland and east 

 of Ulricehamm, to 1,100 feet ; at Jonkoping, in Smaland, near to 

 Lake Almesakra, to about 1,000 feet ; but Tornebohm informed 

 Mr. Geikie that in the northern parts of the country they occur 

 at an elevation of 2,000 feet." Their height varies, the average 

 being about 50 or 100 feet high, but in many places they run up to 

 100 metres or more, while they sometimes sink to 20 or 30 feet. 

 Their breadth, too, varies, the normal breadth being from 30 to 50 

 paces, but in some cases, as at Upsala, where there is a spreading 

 node, their breadth runs to 200 or 250 yards. From these facts the 

 cubical contents of the asar may be guessed. They are often 

 somewhat wider and higher at their northern end, that is, at their 

 inception, than further on. In the low flat country their contour is 

 very uniform, but in the upper and more hilly districts, where they 

 chiefly abound, they have a tendenc}' to become broken up into 

 strings of separate mounds and kame-like masses. Their materials, 



