90 IOWA ACADEMY OF SCIENCES. 



published in the first volume of the Kansas university survey. * 



The upper limestone is gray and is especially characterized 

 by the fossil Syntrialasma hemipUcata; it is widely known as 

 the " Syntrialasma Zone. " 



Lawrence Shales. — The name was suggested by Haworthf for 

 the greater part of the shales lying between the Stanton 

 (Plattsburg or Garnett) and Plattsmouth (Orea'S) limestones. 

 Afterwards the term was extended J to include all of the shales 

 occurring between the two limestones mentioned, and the 

 maximum thickness placed at 300 feet. It was fully described§ 

 the year following. A thin limestone layer, forty to seventy- 

 five feet from the base, which is found in southeastern Kansas, 

 has received the special name of Strawn limestone and Ottawa 

 limestone. In the Missouri River section the limestone near 

 the middle of the Lawrence formation becomes an important 

 member, but its exact relations to the similarly situated lime- 

 stones in southeastern Kansas is not known. Along the Mis- 

 souri river the median calcareous member is called the latan 

 limestone; the argillaceous member beneath, the Weston 

 shales and the one above the Andrew shales. |1 



Plattsmouth Limestone. — The typical section of the Platts- 

 mouth limestone early attracted attention. Owen visited the 

 locality more than fifty years ago. From the same limestone 

 at Belleview, a few miles away, he collected a number of char- 

 acteristic fossils. 1 He, however, thought that the rocks exposed 

 along this part of the Missouri river belonged to the Carbonif- 

 erous limestone series (Mississippian), and they were so colored 

 on his map. The marked dip to the southward, which he per- 

 ceived below the mouth of the Platte river, probably lead him 

 to believe that the coal measures were deposited in a shallow, 

 saucer- shaped basin, of which the opposite rim was near the 

 Mississippi river. 



Swallow,** though he mistook the limestone as exposed at 

 Belleview to be the same as that at Parkville and Weston 

 (Stanton limestone), referred the formation to the upper coal 

 series or upper coal measures. During the same year there 

 appeared a geological map of the United States, by Marcou, f f 



♦University Geol. Sur. Kansas, Vol. 1, p. 159, 1896. 



tKansas Univ. Quart., Vol. II, p. 122, 1894. 



*lbid., Vol. Ill, p. 277, 1895. 



§ University Geol. Sur. Kansas, Vol. I, p. 160, 1896. 



II American Geologist, Vol. XXIII, p. 306, 1899. 



1 Geol. 8ur. Wisconsin, Iowa and Minnesota, p. 134, 1853. 



** Missouri Geol. Sur., 1st and 2d Ann. Repts., p. 79, 1855. 



+t Bull. Soc. G6ol. de France, Tome XII, 1855. 



