THE SVlNAFELL LAYERS 379 



forward between SvinafellsjokuU and Falljokull (PI. II, 1). The gravel plain 

 west of Svinafellsfjall is about 120 m above sea level and from this plain the 

 steep west face of the mountain rises about 450 m. On this west face the 

 Svinafell layers are exposed for a distance of 1.7 km, between the ravine 

 Snidagil in the south and the north edge of Skjolgil in the north. For a distance 

 of 1.2 km between the Godagil and Snidagil ravines, the layers form the base 

 of the mountain and can be clearly seen from the highway to the west where 

 their hght yellow-brown color contrasts strongly with the darker surround- 

 ings (cf. Pis. II and III). It is really curious that they have not previously 

 attracted the attention of geologists. It should be noted, though, that Henson 

 (1955, p. 45) mentions "a sandstone formation in the succession of Svinafell" 

 without further description. The layers are also exposed in a small spot, 

 named Gapar, on the eastern face of Svinafellsfjall. 



S. Bjornsson has informed the author that on Skeidararsandur, in the area 

 between the Skeidara river and the tourist hut, are boulders and blocks of 

 material very similar to the Svinafell layers, and in the spring of 1959 he 

 found distinct plant remnants, bits of grass and unclassified foliage, in one 

 such block. These blocks must once have been /// situ either beneath Skeidar- 

 arjokuU or in the mountains along the eastern margin of that glacier and 

 thus at least 20 km distant from Svinafell. Whether these sediments are of the 

 same age as the Svinafell layers is an open question. Furthermore it should 

 be mentioned that both Bjornsson and the author have observed a layer of 

 bedded sediments, about 30 m in thickness, in Breidamerkurfjall on the eastern 

 side of Orsfajokull. On closer examination Bjornsson has not succeeded in 

 finding any plant remnants in these layers, and in the author's opinion they 

 are probably older than the Svinafell layers, although most likely of Pleisto- 

 cene age. Their bedding is graded and they are probably glaciolacustrine. 

 Petrified boulders of varied glacial sediments from this area have been des- 

 cribed by Tryggvason (1952, pp. 96-98). 



THE STRATIGRAPHY OF SVINAFELLSFJALL 

 AND THE SVlNAFELL LAYER 



As mentioned above, the Svinafell layers formi the base of Svinafellsfjall 

 south of Godagil. North of that ravine the base of the layers rises gradually 

 towards the north, but the contact is visible in only a few places because of 

 scree and soil cover. Just north of Skjolgil the base of the layers is about 160 m 

 above the plain and their thickness is about 15 m. The underlying basalt 

 layers there are normally magnetized down to a layer about 100 m below the 

 sediments, but farther down all layers are reversed. In the reverse layers some 

 of the amygdoils are partly filled with crypto-crystalline quartz, and these 

 layers are on the whole more old-looking than the normally magnetized 

 overlaying layers. There may be a hiatus between the two groups, although a 

 clear erosion contact is not exposed (cf. Fig. 3). 



