XIII.— 
XIV, 
XV, 
XII.— Scalenohedrons of Calcite parasitic on crystals of Natrolite. 
Natrolite and Prehnite supporting sequent Calcite. 
A filamentary mineral on a thin coating of Diabantite on trap and sup¬ 
porting parasitic crystals of various minerals. 
A filamentary mineral in a cavity between crystals of Datolite and Cal¬ 
cite. 
Apophyllite and Analcite on Datolite. 
Calcite sequent on Stilbite. 
Pectolite sequent upon a plate of Prehnite. 
Pyrite in prisms and cubes on Heulandite. 
Succession of Sedimentary Strata in Patagonia and the Pampas Region. 
Tranchee de Foret. 
Grande Couche in l’Esperance. 
XVI.— Tranchee de l’Esperance. Nonconformity between the Grande Couche 
and the overlying dark shales. 
Tranchee de l’Esperance. Westerly wall exhibiting irregularity of de¬ 
posit of Gres Noirs above and gray shales below. 
XVII.— Tranchee de 1’Esperance. Southwesterly corner showing structure of 
the Gres Noirs group. 
Tranchee de l’Esperance. Southerly wall showing faulting in the dark 
shales. 
XVIII.— Glissement de l’Esperance. Southerly wall of l’Esperance. 
Tranchee de Longeroux. Recumbent fold in black shales of Gres Noirs. 
XIX.— Tranchee de Longeroux. Upper sandstone and black coaly shales of 
Gres Noirs. 
Tranchee de Longeroux. Grande Couche at left; dark shales and folded 
sandstones of Gres Noirs in background. 
XX.— Tranchee de Longeroux. Fault between Grande Couche below and dark 
shales above. 
Tranchee de Longeroux. Glissement de l’Esperance and flexed dark shales. 
XXL— Acanthodenus Marshi F. Cambridge. Epigynum. 
Orchcstina saltabunda Simon. Male palpus. 
Idem. Side view of spider without legs. 
Melanophora rufula Banks. Male palpus. 
Spermophora meridionalis Hentz. Male palpus. 
Theridionexus cavernivolus sp. nov. Male palpus. 
Idem. Epigynum. 
Young female. 
Epigynum and lungs. 
Alcimosphenus bifurcatus sp. nov. 
Micrathena horrida Taczanovsky. 
Idem. Abdomen from above. 
Idem. Side view of abdomen. 
Micrathena oblonga Taczanovsky. 
Idem. Side view of abdomen. 
Micrathena sordida Taczanovsky. 
Idem. Side view of abdomen. 
Micrathena Vigorsii Perty. Sternum. 
Idem. Epigynum and lungs. 
Idem. Abdomen from behind. 
Idem. Side view of abdomen. 
XXII.— Epicadinus tuberculatus sp. nov. Adult female. 
Idem. Epigynum. 
Epigynum. 
Epigynum and lungs. 
