On the Erratic Phenomena of Scandinavia. 235 



on the small islands adjoining, from Arendal on the one side, 

 and from Gottenburg on the other, to Christiana, the diluvial 

 grooves present characters of a special nature, — characters 

 which are rarely exhibited in so distinct a manner in the 

 other parts of Scandinavia. We find, in this zone, a great 

 number of narrow and deep furrows, having polished and 

 striated sides, which are a little variable in their dimen- 

 sions ; one set of them having a breadth of from about 10 to 

 20 inches (25 to 50 centimetres), and a depth of from 1^ to 

 2 and 3 yards ; and the other set having a breadth of from 

 1 to 2 and 3 yards, and a depth varying from 1^ to 2 and 

 even 3 times the breadth. We remark, moreover, many cy- 

 lindroid canals passing into the broad grooves, of which the 

 depth is from about a foot to a yard, and the breadth about 

 the same. Among these canals there are some which are 

 rectilinear, but many of them which are much undulated, or 

 follow a serpentine course, and present sinuosities that ap- 

 proach one another very nearly ; frequently they bifurcate, 

 and become divided into several branches, which again unite 

 at a little distance off. The axis of these furrows and the 

 striaB which we see in their interior, have the same general 

 direction as the grooves of the surrounding country, and it is 

 evident that the whole are dependent on one and the same 

 phenomenon. I have observed the same characters on 

 very different kinds of rocks, viz., on various granites, on the 

 zircon syenites, on diorite, and also on slaty rocks, such as 

 gneiss, mica-slate, and hornblende-slate. 



Another very important character which I have observed 

 in many localities in Sweden and Norway, is the existence of 

 striae and grooves on overhanging cliffs, whose inclination to 

 the horizon varies from 90 to 20 degrees ; and the grooves 

 exist, not only near the rounded edge of the overhanging 

 cliflF, but they also extend beneath that edge for a distance 

 of some yards. 



The characters which I have now briefly enumerated shew 

 that the grooving agent or apparatus must have been soft, 

 flexible, and susceptible of very great mobility, in order that 

 it should be able to fill a greater or smaller space, to divide 

 with facility into several branches and then again to unite 



