344 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
localities of which only a few will be considered. One of the best 
exposures of the beds immediately above and below the Dayia flags 
is that of Lau Canal. This section has been described in detail by 
Munthe ! and I merely wish to call attention to a few of the lithic and 
faunal variations. At the northwestern end of the canal the lithology 
is that of grayish blue laminated shales in which fossils — Atrypa 
reticularis excepted — are not common. Proceeding southeastward, 
a rising dip leads to a reef-like mass of limestone. This is composed 
of tabulate and stromatoporoid corals and is succeeded by jointed 
shales filled with an abundance of rhynchonelloids. Another small 
coral reef follows and, after that, another mass of shales similar to 
those first described and with an equal paucity of fossils. Rhyncho- 
nelloids are very uncommon in the first and third shales; but extremely 
abundant in the shales between the coral masses, while large specimens 
of Atrypa reticularis are relatively common in the first and third 
sections of shales, but are hardly present in the second. All of this 
variation may be seen in less than fifty feet, and the strata in question 
are believed to be of the horizon of the Ilionia bed. 
Another excellent place to observe horizontal lithic and faunal 
variations is at Hoburgen klint in the higher beds of reef and other 
- limestones. In the klint the great unstratified masses of coral rise 
many feet, and are bordered on each side by stratified crystalline and 
other limestones of a quite different lithic and faunal aspect, the latter 
deposits filling up the irregularities in the sides of the former. The 
interfingering of coral and sediment and the irregular contacts are 
extremely striking and instructive. These latter strata generally dip 
away from the reef. Still another excellent place to study the varia- 
tion in sediments is Burgen Ridge, on the northern side of which a 
mass of hard reef limestone is underlain by shaly reef and crinoidal 
limestone, this being limited below by the Dayia flags. On the 
southern side, on the contrary, the rock occupying exactly the same 
stratigraphic position consists of odlite and limestone conglomerate 
(Plate 5, fig. 2) with pebbles up to an inch in diameter, sandy lime- 
stone, and calcareous shales and limestones underlain by the lower 
Sphaercodium bed and the Dayia flags. On the northern side Sphae- 
rocodium has not been noted. All of these variations occur in about 
one fourth mile. Another excellent locality is on the island of Storo 
Karlso where numerous fine exposures may be seen in the sea cliffs 
in which faunal and sedimentary variation are shown. Dozens of 
1 Munthe. Sveriges geologiska unders., 1902, ser. C. no. 192, p. 9. 
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