ee

92

in a previous report (McLearn, 1944), belong to the upper part of the Fort
St. John group. It was from them that Selwyn in 1875 collected Neogastro-
plites cornutus (Whiteaves). Other species from the same beds are Neo-
gastroplites selwyni, Nucula dowlingi, and Posidonomya nahwisi (McLearn,
1944). These are characteristic fossils of the Goodrich formation. As
they occur in shale, however, and no sandstone has been recorded from the
section in the cliffs east of Cache Creek, it is apparent that the Goodrich
formation does not extend this far east.

It is not known how far below river level these ‘Shaftesbury’ shales
extend. It is probable, however, that they are underlain by the Gates and
Moosebar formations. These formations, as already noted, are known in
the western sections. If they, as Allan and Stelek (1940) claim, can be
recognized as far east as the Guardian No. 1 well at Bonanza, Alberta, it
can be reasonably inferred that they occur in an intervening area, between
Cache Creek and Alces River, even if below river level.

Age and Correlation
(Sce Figure 12)
Local Correlation

The first serious attempt to co-ordinate stratigraphic information on
the Lower Cretaceous of the western interior of Canada was by McLearn
in 1932. By this time the study of the Canadian Lower Cretaceous faunas
had progressed sufficiently to undertake correlations based on fossils, and
to permit some interpretation of the paleogeography. The work of
L. F. Spath of the British Museum of Natural History on the ammonoid
family Hoplitidae and some Lower Cretaceous ammonoidea from India,
appearing at about this time, was also a contributing factor to an under-
standing of the Canadian faunas. Later, correlations and paleogeography
were revised and extended after revision by Spath (1942) of the age of the
Lemuroceras fauna of India and Madagascar; Wickenden and Shaw’s (1943)
study of the section on Pine River; Beach and Spivak’s (1944) study of the
section in the Peace River Foothills; Hage’s (1944) examination of the
sections in Halfway, Sikanni Chief, and Buckinghorse Valleys; Williams’
(1944) study of the section on the Alaska Highway, west of Fort Nelson;
Kindle’s (1944) examination of the section on Liard River; Hage’s (1945)
study of the section on the Lower Liard; Feniak’s (1944) work in the
‘Athabaska-Barrhead map-area’; and studies by geologists in the employ of
oil exploration companies. Information was also obtained from an un-
published report by C. R. Steleck (1941) and from a recent paper by
Wickenden (1948) on the Lloydminster area of Alberta and Saskatchewan.

Local correlations of Lower Cretaceous formations of northeastern
British Columbia have been considered in recent reports by McLearn
(1944B, 1945). In them the evidence furnished by marine invertebrates,
on the one hand, and by similar lithology and stratigraphic position, on the
other, was found to apply. For convenience these sources will be referred
to as the faunal and lithological evidence respectively. The first is the
only reliable source of long distance correlation. The second can commonly
be applied to short distance correlation, in which marker horizons are
traced from one locality to another. It has been the experience of Canadian