I need a summary for chapters 4 and 6; can you help me with this?

Chapter Four summary:

In this chapter, the Adventure Club members are hoping to hike along Levy or Levart Lake at night. To get there, they have to make their way through Tony's woods. As they walk, Q pipes up that he is afraid the woods might contain spiders, and Hooter is sure that the place is crawling with snakes. Tony assures them that they have far more to fear from the legend of the lake.

He contends that the lake has the reputation of being haunted and that people would often disappear at the lake, never to be heard from again. Tony admits that some people did return after their disappearance, but they were never the same again, often exhibiting strange habits upon their return. Many of them also had fantastic stories to relate about their disappearance. Tony cites his grandfather's best friend, Adam Hibbs, who disappeared during a camping trip. 

Accordingly, Tony's grandfather awakened one night to find Adam in a rowboat on the lake. Although he called to his friend, Adam never gave any indication that he heard the call. After Adam's disappearance, five more people disappeared within the space of fifty years. The story was the same each time: a strange rowboat was always involved, and all disappearances occurred under a three-quarter moon.

Chapter Six summary:

This chapter finds all the children in the middle of the lake in a strange rowboat. In the previous chapter, Katie disappears without warning. When the boys find her climbing into a strange boat, they frantically call out to her. However, she does not hear them, and the boys, caught in the same trance, soon follow her into the same boat.

All are soon awakened to find themselves in the middle of a raging river during a snowstorm. While everyone is holding on for dear life, Katie suddenly stands up in the middle of the boat.

Matt and Hooter try to grab on to Katie, but she soon disappears completely. When the boys' desperate cries yield no answer, Matt fears the worst. Visibility is almost non-existent, as they drift dangerously along the icy river. Matt worries about how he will break the news to his parents. Meanwhile, Q's flashlight illuminates the inscription on the inside of the boat: Emit Levart. Tony reminds the other boys of his grandfather's words, that this name is tied up in the mystery of Levart or Levy Lake.