REPORT OF THE DIRECTOR I9I7 191 



pisolitic and oolitic sedimentary ores and in every case has obtained 

 such a gelatinous residue. Indeed, in cases of spherules of similar 

 size, it is difficult to distinguish residues of modern origin from 

 those of the Clinton ores. 



In order to determine whether or not the similarity extends to 

 the presence of ferrous iron or even ferrous silicate in the modern 

 ores, Professor Morley determined FeO and soluble silica in seven 

 modern lake ores, with the results shown below. 



For six of the specimens from which the samples for analysis 

 were taken, the writer is indebted to the kindness of Prof. J. H. L. 

 Vogt of Christiania, Norway (nos. 13, 14 and 15), Dr Emil Sarlin 

 of Helsingfors, Finland (nos. 16 and 17), and Dr C. Wesenberg-Lund 

 of Copenhagen, Denmark (no. 18). Number 19 was purchased 

 from F. Krantz of Bonn, Germany. 



13 14 15 16 17 18 19 



(614)* (615)* (621)* (580)* (616)* (631)* (2381)* 



FeO 0.72 0.13 1.90 1.29 1.38 0.34 1.49 



Si0 2 in HC1. . . . 1.44 2.13 1.43 1.42 0.88 1.40 1.33 



Si0 2 in KHO. . . 0.81 0.38 1.50 0.37 0.90 n.97 0.34 



Total sol. S1O2. . 2.25 2.51 2.93 1.79 1.78 13.37 .1.67 



* Princeton catalogue number. 



13 Pisolitic limonite (lake-ore), Widastern, Aminne, Smaland, Sweden. E. W. 

 Morley, analyst. 



14 Limonite (lake-ore " Shilling ore "), Bolmen, Aminne, Smaland, Sweden. 

 E. W. Morley, analyst. 



15 Oolitic limonite (lake-ore), Herresbad, Aminne, Smaland, Sweden. E. W. 

 Morley, analyst. 



16 Pisolitic limonite (lake-ore), Suontsenjaroi, Joutse, Finland. E. W. Mor- 

 ley, analyst. 



17 Pisolitic limonite (lake-ore), Palkjaroi, Finland. E. W. Morley, analyst. 



18 Pisolitic limonite (lake-ore), Lake Fureso, Frederiksdal, Denmark. E. W. 

 Morley, analyst. 



19 Pisolitic limonite (lake-ore), Binnensee, Husaby, Sweden. E. W. Morley, 

 analyst. 



The material represented by analysis number 14, as its familiar 

 name suggests, is largely composed of lenticular masses with a 

 diameter of about 1 inch. 



Analysis 15 is made from material which consists of small, uniform 

 spherules strikingly similar to those of the oolitic Clinton ores, 

 differing from them only in color. 



Analysis 18 represents material of particular interest in con- 

 taining many shells coated and replaced by limonite 1 and giving 

 the same siliceous residue that the ordinary spherules do. Thus 



1 Wesenberg-Lund, C, Studier over Sokalk, Bonnemalm og Sogytje i danske 

 Indsoer; Medd. Dansk. Geol. For., no. 7, p. 79-87, 159, plates I and II, 1901. 



