Chapter 11 Study Guide on Continental Drift, covering evidence like fossil and rock clues, magnetic evidence, and seafloor spreading.

Problem Overview:

The task involves completing an outline about Continental Drift using the provided clues and evidence. The outline is divided into two main sections: Early Evidence and Later Evidence (Sea Floor Spreading). The goal is to fill in the blanks with appropriate terms or phrases related to continental drift.

---

Solution:

#### I. Early Evidence
This section focuses on the initial observations and clues that supported the theory of continental drift.

1. A. Puzzlelike fit of continents
- This refers to the observation that the shapes of continents, particularly South America and Africa, appear to fit together like puzzle pieces. This was one of the earliest clues suggesting that continents were once joined.

2. B. Fossil Clues
- These are fossils of organisms found on different continents that suggest a shared ancestry or past connection.
- 1. Mesosaurus: A fossil reptile found in both South America and Africa, indicating these continents were once connected.
- 2. Glossopteris: A fossil plant found in multiple southern continents (South America, Africa, India, Australia), supporting the idea of a supercontinent called Gondwana.
- 3. Cynognathus: Another fossil reptile found in both South America and Africa, providing further evidence for their past connection.

3. C. Glacial Deposits
- These are geological features left by glaciers, such as striations and moraines, which are found in patterns consistent with the idea that continents were once part of a larger landmass.
- 1. Tillites: Layers of glacial debris found in southern continents, indicating they were once part of a large ice sheet centered around the South Pole.
- 2. Glacial deposits: Physical evidence of ancient glaciers, showing similar patterns across continents like South America, Africa, and Antarctica.

4. D. Rock Clues
- These involve similarities in rock types and structures across continents, suggesting they were once part of the same landmass.
- Example: Similar mountain ranges (e.g., Appalachian Mountains in North America and Caledonian Mountains in Europe) indicate a shared geological history.

---

#### II. Later Evidence: Sea Floor Spreading
This section focuses on more modern evidence from oceanic studies that support the theory of continental drift.

1. A. Magnetic Evidence
- This involves the study of Earth's magnetic field recorded in rocks on the ocean floor.
- 1. Newer rock near mid-ocean ridge: Rocks formed closer to the mid-ocean ridges are younger because new crust is continuously being created there.
- 2. Reversal of magnetic alignment of rocks: The Earth's magnetic field has reversed many times in its history, and this is recorded in the rocks on the ocean floor. The pattern of magnetic reversals forms symmetrical stripes on either side of the mid-ocean ridge.
- 3. Ocean rock younger than continental rock: Rocks on the ocean floor are generally younger than those on the continents, as the oceanic crust is constantly recycled through subduction.

2. B. Known reversal of Earth’s magnetic field
- This refers to the well-documented phenomenon where Earth's magnetic poles have flipped numerous times over geological history. This evidence is crucial for understanding the movement of tectonic plates.

---

Final Completed Outline:

#### Evidence for Continental Drift
I. Early Evidence
- A. Puzzlelike fit of continents
- B. Fossil Clues
1. Mesosaurus
2. Glossopteris
3. Cynognathus
- C. Glacial Deposits
1. Tillites
2. Glacial deposits
- D. Rock Clues

II. Later Evidence: Sea Floor Spreading
- A. Magnetic Evidence
1. Newer rock near mid-ocean ridge
2. Reversal of magnetic alignment of rocks
3. Ocean rock younger than continental rock
- B. Known reversal of Earth’s magnetic field

---

Explanation:

1. Puzzlelike Fit of Continents: The jigsaw-like fit of continents, especially South America and Africa, was one of the first clues that suggested continents could move.
2. Fossil Clues: Identical fossils found on separate continents (e.g., Mesosaurus, Glossopteris, Cynognathus) indicated that these continents were once connected.
3. Glacial Deposits: Evidence of ancient glaciers, such as tillites, showed that continents like South America, Africa, and Antarctica were once part of a larger landmass.
4. Rock Clues: Similarities in rock types and structures across continents provided additional evidence for their past connections.
5. Magnetic Evidence: The discovery of symmetrical magnetic stripes on either side of mid-ocean ridges confirmed the process of sea floor spreading.
6. Known Reversal of Earth’s Magnetic Field: This phenomenon helped scientists understand the timing and direction of plate movements.

---

Final Answer:

\boxed{
\begin{aligned}
&\text{I. Early Evidence} \\
&\quad \text{A. Puzzlelike fit of continents} \\
&\quad \text{B. Fossil Clues} \\
&\quad \quad 1. Mesosaurus \\
&\quad \quad 2. Glossopteris \\
&\quad \quad 3. Cynognathus \\
&\quad \text{C. Glacial Deposits} \\
&\quad \quad 1. Tillites \\
&\quad \quad 2. Glacial deposits \\
&\quad \text{D. Rock Clues} \\
&\text{II. Later Evidence: Sea Floor Spreading} \\
&\quad \text{A. Magnetic Evidence} \\
&\quad \quad 1. Newer rock near mid-ocean ridge \\
&\quad \quad 2. Reversal of magnetic alignment of rocks \\
&\quad \quad 3. Ocean rock younger than continental rock \\
&\quad \text{B. Known reversal of Earth’s magnetic field}
\end{aligned}
}