Slow Heart Beat (Bradycardia) An abnormally slow sinus heart rate is called the âsick sinus syndromeâ and, if severe, results in symptoms of fatigue. In some such cases a permanent pacemaker is needed to be implanted to generate a normal heart rate. Many people with sick sinus syndrome also develop atrial fibrillation.
Petrified wood (from the Greek root petro meaning rock or stone; literally wood turned into stone) is the name given to a special type of fossilized remains of terrestrial vegetation. It is the result of a tree or tree-like plants having completely transitioned to stone by the process of permineralization.lements such as manganese, iron, and copper in the water/mud during the petrification process give petrified wood a variety of color ranges. Pure quartz crystals are colorless, but when contaminants are added to the process the crystals take on a yellow, red, or other tint.
Various types of petrified woods are found in. virtually every part of Texas. Also see numbers 8, 10, 11,13, and. 19. 23. Another example of fossils in limestone (also see numbers 3 and. 6) are these bivalve molds. This stone is a popular building ma-.