Polaris is currently the North Star, but it has not always been so due to the precession of the Earth's axis, which causes the direction it points to trace out a cone over 26,000 years. Precession is caused by the gravitational attraction of the Moon and Sun on the Earth's equatorial bulge. While graptolite fossils are found from the Cambrian to Pennsylvanian periods, Clonograptus is best for indicating the Early Ordovician, and a fossil found at 43°N 73°30'W would have been in the Taconic Mountains of New York.

2. January 25, 2019 — 9:15 a.m. to 12:15 p.m.,
• Section B-1

3. At present, the star known as Polaris is the North
Star. However, Polaris has not always been the
North Star
• At each position in Earth’s orbit, the North Pole is pointing toward
• (1) Pollux
• (2) the Sun
• (3) Polaris
• (4) the Moon

4. Polaris is the North Star

5. • The Earth spins on its "axis". This axis is an imaginary line running
through the Earth. If you were to be high above the Earth, looking
straight down along the axis, all the points on Earth would appear to
move in circles around the axis. If you followed this axis out into
space from the northern hemisphere on Earth, it would point toward
a particular star in the sky. We call that star the "North Star" since it
sits in the direction that the spin axis from the northern hemisphere
of Earth points.
• At present, the star known as Polaris is the North Star. However,
Polaris has not always been the North Star

6. • The spin axis of the Earth undergoes a motion called precession. If
you have ever watched a spinning top, you know that its spin axis
tends to stay pointed in the same direction. However, if you give it a
slight nudge, the axis will start to change its direction, and its motion
traces out a cone. This changing of direction of the spin axis is called
precession. So what gave the Earth the "nudge" it needed to start
precessing?

7. • The Earth bulges out at its equator, and the gravitational attraction of
the Moon and Sun on the bulge provided the "nudge" which made
the Earth precess. It was the ancient Greek astronomer and
mathematician Hipparchus who first estimated the precession of the
Earth's axis around 130 B.C. The period of precession is about 26,000
years. In other words, it takes 26,000 years for the axis to trace out
the cone one complete time.

8. Polaris is the North Star

9. • Earth revolves around the Sun at the rate of approximately
• (1) 1° per day (3) 15° per hour
• (2) 360° per day (4) 23.5° per hour

10. • Our orbital speed around the sun is about 67,000 mph (107,000
km/h), according to Cornell.
• We can calculate that with basic geometry. First, we have to figure
out how far Earth travels.
• Earth takes about 365 days to orbit the sun
• See
• https://www.space.com/33527-how-fast-is-earth-moving.html

12. Adapted from
• https://geography.name/the-earths-revolution-around-the-sun/

13. Question 38
• 38. Which graph best shows the hours of daylight that occur at the
equator on all four Earth positions shown?
• Answer is choice 2

14. Questions 39 to 41
• Graptolite Fossils
Although graptolite fossils are found in bedrock from the Cambrian
Period into the Pennsylvanian Period, their remains are most abundant
in Ordovician and Silurian rock layers. During their existence on Earth,
graptolites evolved quickly and spread widely due to ocean circulation.
These tiny and fragile fossils are usually found in dark shales that
formed in marine environments. They are rare in sandstones or other
rocks that formed near shore.

15. 39 . . . . . . 4
• Which graptolite from the data table would best serve as an Early
Ordovician index fossil?
• (1) Climacograptus (3) Didymograptus
• (2) Clonograptus (4) Goniograptus

16. Goniograptus

17. Clonograptus (Goniograptus) sp. nov. Possesses long stem internodes, each consisting of but one
theca. x2J^ would suggest, the writer is not prepared to assert.

18. 40 . . . . . . 2
• A Clonograptus fossil was found in the surface bedrock at 43° N 73°30
W. In which New York State
• landscape region was this fossil found?
• (1) Adirondack Mountains (3) Allegheny Plateau
• (2) Taconic Mountains (4) Champlain Lowlands

19. Taconic Mountains

20. Taconic Mountains

21. 41 . . . . . . 2
• 41 Which graptolite lived at the same time that large amounts of salt
and gypsum were deposited in evaporite
• basins in New York State?
• (1) Clonograptus (3) Didymograptus
• (2) Cyclograptus (4) Goniograptus

22. Cyclograptus

23. 42. . . . 1
• Which statement best describes the arrival of P-waves and S-waves
recorded at a station located closer to the
• epicenter of this same earthquake?
• (1) The time difference between the arrival of the fi rst P-wave and S-
wave would be less than 4 minutes.
• (2) The time difference between the arrival of the fi rst P-wave and S-
wave would be greater than
• 4 minutes.
• (3) P-waves would be recorded, but no S-waves would arrive.
• (4) S-waves would be recorded, but no P-waves would arrive.

24. The time difference between the arrival of the fi
rst P-wave and S-wave would be less than 4
minutes.

25. 43 . . . .1

26. 43 . . . . . . 1
• The rock movement that caused the earthquake occurred 10
kilometers below Earth’s surface. In which
• Earth layer did this earthquake originate?
• (1) lithosphere (3) stiffer mantle
• (2) asthenosphere (4) outer core

27. lithosphere

28. 44 . . . . . . 4
• If the center of the low-pressure system follows a normal storm track,
toward which city would the center of
• this low most likely move?
• (1) Buffalo (3) New York City
• (2) Elmira (4) Plattsburgh

29. http://www.mephamearthscience.org/weath
er%20review%2017%20key.pdf

31. 45 . . . . . . 3

32. 46 . . . . . . 3

33. 47 . . . . . . 3

34. 48 . . . . . . 1

35. 49 . . . . . . 2

36. 50 . . . . . . 4 ..

37. 39 . . . . . . 4
• A Clonograptus fossil was found in the surface bedrock at 43° N 73°30
W. In which New York State
• landscape region was this fossil found?
• (1) Adirondack Mountains (3) Allegheny Plateau
• (2) Taconic Mountains