Plate. 9. — Thin Sections of Material from Meriden "Ash Bed " and north Locality. 



Figure 1. — Mixture of sand and glass fragments from the Meriden "ash bed." 

 The sand at the top runs down between two fragments, which are 

 red brown glass at center, much changed to calcite, with lighter 

 devitrification border of a yellow color, which is altered to a fibrous 

 plagioclase, and an outer cord of highly refringent glass, which is 

 broken and moved in places, letting the glass out among the sand 

 grains. This is best seen on the inner border of the right-hand 

 piece. Along the upper edge of this piece is a band of colorless 

 glass (dark in the photograph), which is changed to calcite. There 

 is a curve in the border line above the center where a spherulite 

 has slipped out. The right-hand piece shows two spherulites, the 

 left-hand one, several serpentinized olivines. Magnified 20 times. 

 See page 75. 



Figure 2. —Sand cemented by glass into a hard quartzite. The slide has been 

 treated with HC1 and KHO, and the brown portion of the glass has 

 been in part dissolved, so that threads cross the empty spaces and 

 join the refringent cord of glass that bounds each sand grain. Near 

 basal bed at the Meriden "ash bed." See page 75. Magnified 85 

 times. 



Figure 3. — Fragment of black aphanitic diabase melted at the border into a blebby 

 glass and with a thread of glass going out from it. In breccia in 

 throat of the mud volcano at the north locality at Meriden. See 

 page 76. Magnified 20 times. 



Figure 4. — Rare fragment of amygdaloid in glass breccia. From north locality at 

 Meriden. See page 77. Magnified 28 times. 



Figure 5.— Several varieties of trap in one slide ; (1) aphanitic trap, with large frag- 

 ments of altered orthoclase, showing that it solidified after the in- 

 troduction of foreign material and was then shattered and carried 

 upward and mingled with other varieties, (2) amygdaloidal trap, (3) 

 hyalopilitic trap in center. North locality at Meriden. See page 78. 

 Magnified 20 times. 



(86) 



