140 SLATE DEPOSITS AND INDUSTRY OF UNITED STATES. 
Hall (C. W.). Keewatin area of eastern central Minnesota. 
Bull. Geol. Soc. Am., vol. 12, p. 362, pi. 31, tig. 1. The clay slates, Aug., 1901. 
Harker (Alfred). On slaty cleavage and allied rock structures, with special refer- 
ence to the mechanical theories of their origin. 
Rept. Brit. Assoc. Adv. Science (1885), 1886. 
Harkness (Robert) and Bi.vthe (John). On the cleavage of the Devonians of the 
southwest of Ireland. 
Edinb. New Phil. Jour., new series, vol. 2, No. 4, Oct., 1855. 
Hawks (G. \V. ). Clay slate (argillite). 
Geology of New Hampshire, by (\ II. Hitchcock and others, vol. 3, pt. 4, pp. 236-238. 
Hopkins (W.). On the internal pressure to which rock masses may be subjected, 
and its possible influence on the production of the laminated structure. 
Trans. Camb. Phil. Soc, vol. 8, pp. 456-470; Cambridge, England, 1849. 
1 [oskins ( I.. M.) . Flow and fracture of rocks as related to structure. 
Sixteenth Ami. Rept. F. S. Geol. Survey. 1894-96, ]>t. 1, L896. (Cleavage and lissility. pp. 868-874.) 
Ill tchings | W. Maynard). Clays, shales, and slates. 
Geol. Mag., dec. 1, vol. :;, No. 7, p. 309, and No. 8, p. 343. On slates, pp. 312-314, 343, 344; London, 
1896. 
HuTCHINGS i W. MAYNARD). Ash slates of the Lake district. 
Geol. Mag., London, 1892. 
[nostranzeff (A.). Studien uber metamorphosirte Gesteine iin Gouvernement 
Olonez | Russia). 
Thonschiefer, pp. 137-144; Leipzig, 1879. 
.1 \\\ii \z Ed. I. De la propagation de la chaleur dans les corps; de ses relations 
avec la structure <\v^ mineraux, (2) le inetamorphisnie des roches. 
Hull. Soc. geol. France, 3d ser., vol. 3, pp. 499-510. Experiments with slate, p. 505. See also vol. 
'-', p. 264. 
Jannetaz (Ed.). Relation entre la propagation de la chaleur et 1'elasticite sonore 
dans les roches et dans les corps cristal Uses. 
Bull. Soc. geol. France, 3d ser., vol. 5, pp. 410-426, 1877. Experiments with slate, p. 416. 
Jannetaz (Ed.). Memoire sur les connexions de la propagation de la chaleur avec 
leurs differents clivages et avec les mouvements du sol qui les out produits. 
Bull. So.', geol. France, :;<! ser., vol. 9, p. 196, 1880-81. 
Jannetaz (Ed.). Memoire sur les clivages des roches (schistosito, longrain) et sur 
lour reproduction. 
Bull. Soc. geol. France. 3d ser.. vol. 12, p. 211, 1*83-84. 
Kino i William ). On jointing and its relation to slaty cleavage. 
Trans. Roy. Irish Acad., vol. 25, 1875. 
Lai gel I Auguste). Le Clivage des roches. Bull. Soc. Geol. de France (2), vol. 
12, 1854-1855. pp. 363-368. 
Leitii (C. K.). Rock cleavage. 
Bull. F. s. (ieoi. survey No. 239, 1905. Summary statement of secondary rock cleavage, p. 135. 
Comparison of present statement with previous ones as to secondary cleavage, p. 140. Original 
cleavage, p. 113. 
Lesley (J. P.). A summary description of the geology of Pennsylvania. 
Geo!. Surv. Pa., Final Kept., vol. 1 (The southern or Peach Bottom phyllite belt, pp. 136-141, 555, 
556. Chaps. 45-49, Formation No. 3 and the roofing-slate beds); Harrishurg, 1892. 
Loretz (H.). Ueber Schieferung. 
Bericht iiber die Senckenbergische naturforschende Gesellschaft, pp. 61-116, 1879-80; Frankfurt 
a. M., 1880. 
Loretz (H.). Leber Transversalschieferung und verwandte Krscheinungen in Thii- 
ringischen Schiefergebirge. 
Jahrb. Konigl. Preuss. geol. Landesanstalt und Bergakademie, pp. 25S 306 and pi. 7 (1881); 
Berlin, 1882. 
Mallard (E.). Sur l'examen microscopique de quelques schistes ardoisiers. 
Bull. Soc. mineralogique de France, vol. 3, No. 4, p. 101, 1880. 
