STE. GENEVIEVE MARLS NEAR FORT DODGE 601 



layers. No fossils or limestone bands were observed. Under 

 the shales are exposed twelve feet of gray limestone soooie ot 

 which is well bedded while some is fragmental. The whole series 

 of limestone and sliales rises fifty feet or more above creek level. 



Another outcrop of red and green clay shales occurs about 

 one-fourth mile up the valley from the one just described. Here 

 thirty feet or more of the gray-green shale overlies nodular gray 

 limestone which stands three feet above the water-level. Abund- 

 ant fossils are present in the shales, but a five foot bed of red 

 clay shale above them is quite barren of life forms. 



About four hundred yards above the junction of North and 

 South Lizard creeks, on the east bank of North Lizard, there is 

 an exposure of the gray-green shale which rises twenty-five or 

 thirty feet above the stream. Over this shale lies fifteen to twenty 

 feet of red shale. At several horizons in the gray-green skale 

 there are harder limy ibands which contain large numbers of fos- 

 sil brachiopods. The contact of the red shale with the gray is 

 quite sharp and lies just a'bove a layer of fossiliferous yellow 

 limestone. 



The next exposures on this fork, and so far as is known to the 

 writers the last ones, are a gi-oup five miles up the valley and in 

 the southeast quarter of section 8, Douglas township, about one- 

 fourth mile below the Minneapolis and St. Louis Railroad bridge, 

 on the north bank of the stream. Here a small tributary ravine 

 has been cut through six feet of yellow and green shale, below 

 this through five feet of red and green shale, beneath which is 

 exposed two feet of gray sandstone or sandy limestone, then five 

 feet of shaly material beneath which in turn two feet of green 

 shale is seen above the stream level. Just down the main valley 

 a few rods is an exposure of ten feet of yellow and brownish red 

 clay shale, under which is six feet of red shale which lies on gray 

 sandstone which rises six feet above the creek The red shales of 

 these exposures are for the most part true clay shales, although 

 some are finely sandy. Lithologically they are the equivalent of 

 the red shales overlying the fossiliferous gray-green marls seen 

 in the abandoned clay pit and elsewhere upstream as far as the 

 exposure just above the forks. None of the beds at this locality 

 yielded any fossils nor were there found any of the nodular lime- 

 stone bands w^hich are the fossiliferous members of the exposures 

 farther downstream. Black shales, probably Coal Measures, are 

 said to be present in the valley walls. Just where the tributary 



