The yarn number is the length in yards of one pound of the yarn, divided by 1600. Symbol Nar. This is the same as the weight in ounces of 100 yards. So one pound of number 1 run yarn is 1600 yards long, one pound of number 2 run yarn is 3200 yards long, and so on.
As with most other volcanoes in the Cascade Range, Mount St. Helens is a large eruptive cone consisting of lava rock interlayered with ash, pumice, and other deposits. The mountain includes layers of basalt and andesite through which several domes of dacite lava have erupted.
As part of the Cascade Range of mountains, Mount St. Helens was formed by eruptive flows of magma as the Juan de Fuca tectonic plate is forced under the North American Plate. â¦ Beginning about 37,600 years ago, periodic eruptions and magma flows occurred in the area between Mount St. Helens and Mount Rainer.