TABLE OF CONTENTS. 
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HINTERODUCTORNC ETL: SETS Herd cols See MER a ene ee Ne ree te nib teem rs il 
Tony NATORAD SYSTEM) OF VOLCANIC: IROCGKS)..2...5..-.0.-6----.--+.++-0 foereres 5 
Oxpury HURST) RAW OLEH sere. crcleiersierss eters Ate nO Oke ee CI Renee OE Tee ae 12 
ORDER SECOND: “TRACHYTH),..5 052-2422. eee <1 ee Sree ae aS tare ne he ei Mee F 17 
ENDER BE LHTRD my RO PIII ME ey scarr sie ssts ein oe so la ei Pare eae tS os aoe lap lal see 20 
Orper FourtH: ANDESITE............... Rohe ere SEA DHE eee SRO ERS UCB OS ante COI 25 
ORDERBHURTHE PDA SAINTS er rrarare eri ane vocidir< stots eet ede oe re eee Saunier lc 
CoRRELATION OF THE FivE ORDERS OF VOLCANIC ROCKS.............+......-.-- eee 28 
Laws Relative to the Age of Massive Eruptions............ si efeloye is ays ase areheye 29 
Laws regarding the Mutual Relations of Massive Eruptions and Voleanie Activity 32 
RELATION oF VoLcanic Rocks to ANcreENT Eruptive RocKS..............-.-eeceeeee 35 
Chmelennnvare Age anda Recline reer Soe eee ono ee ad & Soe Sek een a ees ihe 
Correintion0f Age and, ‘Composuiwre <2... onc deste yxeci eee ciet ween ean 41 
Correlation of Eruptive Rocks in regard to their Geographical Distribution... ... 45 
On PrriegORIGUNG OL MV OLGANTO SOCKS aay es iicy sce. 1c its oie wae tae Serae austere ars ites hares 2 = 46 
is OCOD LTC: OEY OUT 107 fe eR <r a 47 
MO MeGiINy AMV OLA ACEO crane tiva a 2 as wats BT OS lowes ee Ge Lee 60 
3. Other Theories regarding the Origin of Volcanic Rocks..... > MOOR eee 6 3de 68 
RELATION OF THE DISTRIBUTION OF VoLcANIc Rocks TO THE CONFIGURATION OF THE SURFACE 
Ors Gri Cane! F oe couaeceeedsoc ROBO COL ODA och CON een oo tp Bee Ons CSTE he: 
